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University of Adelaide
1.
Hardi, Justin S.
Experimental investigation of high frequency combustion instability in cryogenic oxygen-hydrogen rocket engines.
Degree: 2012, University of Adelaide
URL: http://hdl.handle.net/2440/82071 
► Self-sustaining pressure oscillations in the combustion chamber, or combustion instability, is a commonly encountered and potentially damaging phenomenon in liquid propellant rocket engines (LPREs). In…
(more)
▼ Self-sustaining pressure oscillations in the
combustion chamber, or
combustion instability, is a commonly encountered and potentially damaging phenomenon in liquid propellant rocket engines (LPREs). In the high-frequency variety of
combustion instability, the pressure oscillations in the
combustion chamber take on the form and frequency of an acoustic resonance mode of the
combustion chamber volume. The most common mode in naturally occurring instability, and also the most destructive, is the first tangential mode, with acoustic gas oscillations oriented transversally to the direction of propellant injection. The instability is driven by the coupling between acoustic oscillations and unsteady energy release from
combustion. The mechanisms through which injection and
combustion firstly respond to the acoustic field, and secondly feed energy back into the acoustic field have not yet been fully characterised. Shear coaxial-type injectors are common in LPREs. Past experimental and numerical research efforts have investigated the interaction between this type of injector and transverse acoustic fields. Some experimental efforts have successfully forced transverse acoustic modes and studied their influence on shear coaxial injection under LPRE-like conditions. Acoustic forcing of coaxially injected LOx/H₂ has previously been conducted only at low pressures and injection performance levels. This work addresses the lack of experimental data available for the interaction of shear coaxial injection of LOx/H₂ with acoustics under conditions representative of industrial engines. A new experimental rocket combustor, designated ‘BKH’, was developed for investigating the response of a reacting spray of coaxially injected LOx/H₂ to an acoustic field. For characterising the response, simultaneous high-speed recordings of both backlit shadowgraph and hydroxyl radical (OH*) chemiluminescence imaging have been captured through optical access windows. The operating conditions of BKH extend to conditions more representative of actual LPREs than has previously been achieved with LOx/H₂ in studies of flame-acoustic interaction. BKH was run at pressures of 40 or 60 bar, which correspond to subcritical and supercritical thermo-physical regimes for oxygen. Hydrogen injection temperature was ambient, around 290 K, or cryogenic, around 50 K. An array of multiple injectors was used to better represent real engines. A system for modulating the nozzle exhaust flow was used to induce acoustic perturbations inside the
combustion chamber. Two types of perturbation were applied to the near-injection region; oscillating acoustic pressure, and oscillating transverse acoustic velocity. BKH was used to investigate how subcritical or supercritical pressure level and ambient or cryogenic hydrogen injection temperature influence the interaction of acoustic pressure or velocity with injection and
combustion processes. Shadowgraph imaging reveals up to 70% reduction in the length of the oxygen jet when subjected to acoustic velocity of amplitude approaching…
Advisors/Committee Members: Dally, Bassam B. (advisor), Oschwald, Michael (advisor), School of Mechanical Engineering (school).
Subjects/Keywords: rocket engine; combustion; cryogenic; instabilities; combustion instabilities; liquid rocket
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APA (6th Edition):
Hardi, J. S. (2012). Experimental investigation of high frequency combustion instability in cryogenic oxygen-hydrogen rocket engines. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/82071
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Hardi, Justin S. “Experimental investigation of high frequency combustion instability in cryogenic oxygen-hydrogen rocket engines.” 2012. Thesis, University of Adelaide. Accessed February 28, 2021.
http://hdl.handle.net/2440/82071.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Hardi, Justin S. “Experimental investigation of high frequency combustion instability in cryogenic oxygen-hydrogen rocket engines.” 2012. Web. 28 Feb 2021.
Vancouver:
Hardi JS. Experimental investigation of high frequency combustion instability in cryogenic oxygen-hydrogen rocket engines. [Internet] [Thesis]. University of Adelaide; 2012. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/2440/82071.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Hardi JS. Experimental investigation of high frequency combustion instability in cryogenic oxygen-hydrogen rocket engines. [Thesis]. University of Adelaide; 2012. Available from: http://hdl.handle.net/2440/82071
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Cincinnati
2.
Knadler, Michael.
Validation of a Physics-Based Low-Order Thermo-Acoustic
Model of a Liquid-Fueled Gas Turbine Combustor and its Application
for Predicting Combustion Driven Oscillations.
Degree: PhD, Engineering and Applied Science: Aerospace
Engineering, 2017, University of Cincinnati
URL: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511861629413018
► This research validates a physics based model for the thermo-acoustic behavior of a liquid-fueled gas turbine combustor as a tool for diagnosing the cause of…
(more)
▼ This research validates a physics based model for the
thermo-acoustic behavior of a liquid-fueled gas turbine combustor
as a tool for diagnosing the cause of
combustion oscillations. A
single nozzle, acoustically tunable gas turbine
combustion rig
fueled with Jet-A was built capable of operating in the unsteady
combustion regime. A parametric study was performed with the
experimental rig to determine the operating conditions resulting in
thermoacoustic
instabilities. The flame transfer function has been
determined for varying fuel injection and flame stabilization
arrangements to better understand the feedback loop concerning the
heat release and acoustics. The acoustic impedance of the
boundaries of the
combustion system was experimentally determined.
The results were implemented in a COMSOL Multiphysics model as
complex impedance boundary conditions at the inlet and exit and a
source term to model the flame and heat release. The validity of
that model was determined based on an eigenvalue study comparing
both the frequency and growth rate of the eigenvalues with the
experimentally measured frequencies and pressures of the stable and
unstable operating conditions. The model demonstrated that it can
accurately predict the instability of the examined operating
conditions. The model also closely predicted the frequency of
instability and demonstrated the usefulness of including the
experimentally determined acoustic boundary conditions over
idealized sound hard boundaries.
Advisors/Committee Members: Lee, Jongguen (Committee Chair).
Subjects/Keywords: Aerospace Materials; Combustion; Combustion Instabilities; Thermoacoustics; Gas Turbine Combustion
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APA (6th Edition):
Knadler, M. (2017). Validation of a Physics-Based Low-Order Thermo-Acoustic
Model of a Liquid-Fueled Gas Turbine Combustor and its Application
for Predicting Combustion Driven Oscillations. (Doctoral Dissertation). University of Cincinnati. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511861629413018
Chicago Manual of Style (16th Edition):
Knadler, Michael. “Validation of a Physics-Based Low-Order Thermo-Acoustic
Model of a Liquid-Fueled Gas Turbine Combustor and its Application
for Predicting Combustion Driven Oscillations.” 2017. Doctoral Dissertation, University of Cincinnati. Accessed February 28, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511861629413018.
MLA Handbook (7th Edition):
Knadler, Michael. “Validation of a Physics-Based Low-Order Thermo-Acoustic
Model of a Liquid-Fueled Gas Turbine Combustor and its Application
for Predicting Combustion Driven Oscillations.” 2017. Web. 28 Feb 2021.
Vancouver:
Knadler M. Validation of a Physics-Based Low-Order Thermo-Acoustic
Model of a Liquid-Fueled Gas Turbine Combustor and its Application
for Predicting Combustion Driven Oscillations. [Internet] [Doctoral dissertation]. University of Cincinnati; 2017. [cited 2021 Feb 28].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511861629413018.
Council of Science Editors:
Knadler M. Validation of a Physics-Based Low-Order Thermo-Acoustic
Model of a Liquid-Fueled Gas Turbine Combustor and its Application
for Predicting Combustion Driven Oscillations. [Doctoral Dissertation]. University of Cincinnati; 2017. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1511861629413018
Penn State University
3.
Jones, Brian Keith.
Flame Response Mechanisms and their Interaction in a Lean Premixed Swirl-Stabilized Gas Turbine Combustor
.
Degree: 2011, Penn State University
URL: https://submit-etda.libraries.psu.edu/catalog/10638
► To satisfy increasingly stringent environmental regulations, gas turbine engines are run in a lean premixed mode. Unfortunately, operating in this mode greatly increases the flame’s…
(more)
▼ To satisfy increasingly stringent environmental regulations, gas turbine engines are run in a lean premixed mode. Unfortunately, operating in this mode greatly increases the flame’s susceptibility to self sustained
combustion instabilities. It is vital to understand flame dynamics in order to better predict the onset of such
instabilities. At low velocity forcing amplitudes, there are two local flame response mechanisms that affect lean premixed flames: vorticity fluctuations affecting local flame wrinkling, and velocity fluctuations affecting the mean flame surface area. No experimental studies investigating the interaction of these mechanisms and their affect on the global flame response have been reported in the literature.
An experimental study was conducted to determine the effect of the interaction of these two flame response mechanisms on the global turbulent flame response in a lean premixed, swirl-stabilized gas turbine combustor. Premixed natural gas and air were modulated with a siren type modulation device at frequencies between 80 Hz and 360 Hz. Overall chemiluminescence intensity was recorded with photomultiplier tubes equipped with filters for CH*, CO2*, and OH*, and used as a measure of the global flame heat release rate. Hot wire anemometry was used to measure the inlet velocity fluctuation. To characterize flame structure, flame length and shape, CH* chemiluminescence images were recorded at forced and unforced conditions. From chemiluminescence images synchronized in phase with the inlet velocity fluctuation, it was possible to characterize the role of the two flame response mechanisms.
Flame transfer function (FTF) measurements, which quantify the ratio of the flame’s heat release rate response to inlet velocity fluctuations, were made for mean flow velocities of 20 m/s, 25 m/s, and 30 m/s, and equivalence ratios of 0.65, 0.70, 0.75, 0.80 with a normalized velocity forcing amplitude of 5%. It was found that the FTF gain and phase depend on mean velocity, flame length, and flame shape. Particularly interesting, a forcing frequency, defined as fmin, was observed at which there was minimal heat release rate response. This frequency changed with the same parameters that influence the FTF measurements.
Chemiluminescence images revealed two general flame shapes: a typical “V” flame shape and a longer length “V” flame shape with an extension into the corner recirculation zone. Images phase synchronized with the input velocity fluctuation were taken for operating conditions representative of the two flame shapes. For a typical “V” flame, it was revealed that high FTF gain forcing frequency conditions exhibited a constructive interaction of the two flame response mechanisms. Operating conditions with forcing frequencies of minimal gain, fmin, exhibited a destructive interaction of the two mechanisms. For the longer “V” flame shape with an extension into the corner recirculation zone, it was found that the relative magnitude of the two flame response mechanisms, in addition to the phase…
Advisors/Committee Members: Domenic Adam Santavicca, Thesis Advisor/Co-Advisor, Domenic Adam Santavicca, Thesis Advisor/Co-Advisor.
Subjects/Keywords: premixed; flame; instabilities; lean; combustion; gas turbine
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APA (6th Edition):
Jones, B. K. (2011). Flame Response Mechanisms and their Interaction in a Lean Premixed Swirl-Stabilized Gas Turbine Combustor
. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/10638
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Jones, Brian Keith. “Flame Response Mechanisms and their Interaction in a Lean Premixed Swirl-Stabilized Gas Turbine Combustor
.” 2011. Thesis, Penn State University. Accessed February 28, 2021.
https://submit-etda.libraries.psu.edu/catalog/10638.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Jones, Brian Keith. “Flame Response Mechanisms and their Interaction in a Lean Premixed Swirl-Stabilized Gas Turbine Combustor
.” 2011. Web. 28 Feb 2021.
Vancouver:
Jones BK. Flame Response Mechanisms and their Interaction in a Lean Premixed Swirl-Stabilized Gas Turbine Combustor
. [Internet] [Thesis]. Penn State University; 2011. [cited 2021 Feb 28].
Available from: https://submit-etda.libraries.psu.edu/catalog/10638.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Jones BK. Flame Response Mechanisms and their Interaction in a Lean Premixed Swirl-Stabilized Gas Turbine Combustor
. [Thesis]. Penn State University; 2011. Available from: https://submit-etda.libraries.psu.edu/catalog/10638
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Miami University
4.
Wisman, David L, II.
ELECTRIC FIELD INDUCED STABILITY MODIFICATIONS IN PRE-MIXED
HYDROCARBON FLAMES.
Degree: MS, Physics, 2006, Miami University
URL: http://rave.ohiolink.edu/etdc/view?acc_num=miami1154727896
► This work focuses upon the effects of electric fields on the stability of pre-mixed hydrocarbon flames fueled by methane, propane and butane. For all fuels…
(more)
▼ This work focuses upon the effects of electric fields
on the stability of pre-mixed hydrocarbon flames fueled by methane,
propane and butane. For all fuels studied, over varying flow rates
and equivalence ratios, electric-field-induced modification of the
flame front stability over wide ranges has been observed and
documented. Specifically, the electric pressure effect has been
used to force pre-mixed hydrocarbon/air flame fronts to transition
from flow-induced hydrodynamic-instability-dominated behavior, to
field-stabilized laminar flow, and finally to field-induced
thermal-diffusive-instability-dominated turbulent flame fronts. The
effects are best described from a
combustion dynamics viewpoint as
a continuously variable electric-field-induced diminution of the
flame Lewis number from typical values (> 1), past the flame
critical Lewis number (0.6-0.9), to thermal-diffusive-instability
dominated values below the critical Lewis number at higher applied
potentials. A possible field-driven ion chemistry process that
could produce those effects is the dissociative recombination of
the flame ion (H30+) at the burner surface.
Advisors/Committee Members: Marcum, S. Douglas (Advisor).
Subjects/Keywords: Combustion; Flame Instabilities
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APA (6th Edition):
Wisman, David L, I. (2006). ELECTRIC FIELD INDUCED STABILITY MODIFICATIONS IN PRE-MIXED
HYDROCARBON FLAMES. (Masters Thesis). Miami University. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=miami1154727896
Chicago Manual of Style (16th Edition):
Wisman, David L, II. “ELECTRIC FIELD INDUCED STABILITY MODIFICATIONS IN PRE-MIXED
HYDROCARBON FLAMES.” 2006. Masters Thesis, Miami University. Accessed February 28, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=miami1154727896.
MLA Handbook (7th Edition):
Wisman, David L, II. “ELECTRIC FIELD INDUCED STABILITY MODIFICATIONS IN PRE-MIXED
HYDROCARBON FLAMES.” 2006. Web. 28 Feb 2021.
Vancouver:
Wisman, David L I. ELECTRIC FIELD INDUCED STABILITY MODIFICATIONS IN PRE-MIXED
HYDROCARBON FLAMES. [Internet] [Masters thesis]. Miami University; 2006. [cited 2021 Feb 28].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=miami1154727896.
Council of Science Editors:
Wisman, David L I. ELECTRIC FIELD INDUCED STABILITY MODIFICATIONS IN PRE-MIXED
HYDROCARBON FLAMES. [Masters Thesis]. Miami University; 2006. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=miami1154727896
5.
Lamraoui, Ammar.
Acoustique et dynamique de flamme dans un foyer turbulent prémélangé swirlé : application à l'étude du bruit de combustion dans les chambres de turbines à gaz. : Investigating combustion noise and instabilities in a gas turbine combustor : acoustic propagation and flame dynamics.
Degree: Docteur es, Energétique, 2011, Châtenay-Malabry, Ecole centrale de Paris
URL: http://www.theses.fr/2011ECAP0028
► La réduction des émissions de polluants et l’augmentation du rendement des moteurs ont conduit à une large utilisation de régimes de combustion pauvres en carburant…
(more)
▼ La réduction des émissions de polluants et l’augmentation du rendement des moteurs ont conduit à une large utilisation de régimes de
combustion pauvres en carburant dans les foyers de type moteurs aéronautiques et turbines à gaz. Des phénomènes de bruit et d’instabilités de
combustion peuvent alors apparaître. Des fluctuations cycliques auto-entretenues de la pression au sein d’un foyer peuvent conduire à une limitation des régimes de fonctionnement ou une usure rapide et indésirable des installations et dans certains cas une destruction du système. L’objectif de ce travail de thèse est d’étudier les mécanismes responsables du bruit de
combustion et des instabilités dans un foyer turbulent prémélangé swirlé. L’étude repose sur une analyse du champ de pression au sein du foyer, de la dynamique de la
combustion et une caractérisation détaillée des conditions limites en amont, aval et dans les lignes d’alimentation en combustible et en comburant. Le banc expérimental CESAM ("
Combustion Étagée Swirlée Acoustiquement Maîtrisée") est utilisé au cours de ce travail. Basée sur des observations expérimentales, une étude théorique de l’acoustique du foyer est tout d’abord réalisée grâce à un modèle à deux cavités couplées qui modélisent le tube de prémélange et la chambre de
combustion de ce banc. Les fréquences et les structures spatiales des modes propres du foyer sont examinées, et des comparaisons sont menées avec les résultats expérimentaux. La condition limite au fond du tube de prémélange est mesurée, et utilisée comme entrée dans le modèle. L’effet de cette condition sur la prévision des fréquences des modes propres est examiné. Par la suite, le code de calcul AVSP est utilisé pour valider les résultats obtenus avec le modèle couplé. L’interaction entre ces modes acoustiques et la flamme est mise en évidence en caractérisant la dynamique de l’écoulement réactif. La vélocimétrie par images de particules (PIV) à haute cadence est utilisée. Une première étude est menée sur les champs de vitesse moyens et fluctuants puis on s’intéresse à l’analyse spectrale des champs de vitesse instantanés, rendue possible par la haute cadence du diagnostic. Un post-traitement faisant intervenir une méthode de détection des tourbillons est ensuite mis en oeuvre en utilisant le critère _2. Des structures cohérentes sont convectées le long du front de flamme à la fréquence du second mode instable du foyer. Le chapitre précédent ayant permis de montrer que ce mode acoustique était essentiellement associé au tube de prémélange, le mécanisme de couplage est clairement identifié. Par la suite, un traitement en moyenne de phase est appliqué aux champs de vitesse axiale. Des mouvements de battements des bras de la flamme dans les directions longitudinale et transverse sont mis en évidence aux fréquences des modes instables. L’émission naturelle de la flamme est également mesurée avec une caméra rapide. Une analyse spectrale et un traitement en moyenne phase avec transformée d’Abel sont appliqués aux images pour caractériser les régions de la…
Advisors/Committee Members: Ducruix, Sébastien (thesis director).
Subjects/Keywords: Bruit de combustion; Instabilités de combustion; Dynamique de flamme; Combustion noise; Combustion instabilities; Flame dynamics
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APA ·
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APA (6th Edition):
Lamraoui, A. (2011). Acoustique et dynamique de flamme dans un foyer turbulent prémélangé swirlé : application à l'étude du bruit de combustion dans les chambres de turbines à gaz. : Investigating combustion noise and instabilities in a gas turbine combustor : acoustic propagation and flame dynamics. (Doctoral Dissertation). Châtenay-Malabry, Ecole centrale de Paris. Retrieved from http://www.theses.fr/2011ECAP0028
Chicago Manual of Style (16th Edition):
Lamraoui, Ammar. “Acoustique et dynamique de flamme dans un foyer turbulent prémélangé swirlé : application à l'étude du bruit de combustion dans les chambres de turbines à gaz. : Investigating combustion noise and instabilities in a gas turbine combustor : acoustic propagation and flame dynamics.” 2011. Doctoral Dissertation, Châtenay-Malabry, Ecole centrale de Paris. Accessed February 28, 2021.
http://www.theses.fr/2011ECAP0028.
MLA Handbook (7th Edition):
Lamraoui, Ammar. “Acoustique et dynamique de flamme dans un foyer turbulent prémélangé swirlé : application à l'étude du bruit de combustion dans les chambres de turbines à gaz. : Investigating combustion noise and instabilities in a gas turbine combustor : acoustic propagation and flame dynamics.” 2011. Web. 28 Feb 2021.
Vancouver:
Lamraoui A. Acoustique et dynamique de flamme dans un foyer turbulent prémélangé swirlé : application à l'étude du bruit de combustion dans les chambres de turbines à gaz. : Investigating combustion noise and instabilities in a gas turbine combustor : acoustic propagation and flame dynamics. [Internet] [Doctoral dissertation]. Châtenay-Malabry, Ecole centrale de Paris; 2011. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2011ECAP0028.
Council of Science Editors:
Lamraoui A. Acoustique et dynamique de flamme dans un foyer turbulent prémélangé swirlé : application à l'étude du bruit de combustion dans les chambres de turbines à gaz. : Investigating combustion noise and instabilities in a gas turbine combustor : acoustic propagation and flame dynamics. [Doctoral Dissertation]. Châtenay-Malabry, Ecole centrale de Paris; 2011. Available from: http://www.theses.fr/2011ECAP0028
Penn State University
6.
O'meara, Bridget C.
An experimental study of the effect of a pilot flame on technically pre-mixed, self-excited combustion instabilities.
Degree: 2015, Penn State University
URL: https://submit-etda.libraries.psu.edu/catalog/27285
► Combustion instabilities are a problem facing the gas turbine industry in the operation of lean, pre-mixed combustors. Secondary flames known as “pilot flames” are a…
(more)
▼ Combustion instabilities are a problem facing the gas turbine industry in the operation of lean, pre-mixed combustors. Secondary flames known as “pilot flames” are a common passive control strategy for eliminating
combustion instabilities in industrial gas turbines, but the underlying mechanisms responsible for the pilot flame’s stabilizing effect are not well understood. This dissertation presents an experimental study of a pilot flame in a single-nozzle, swirl-stabilized, variable length atmospheric
combustion test facility and the effect of the pilot on
combustion instabilities.
A variable length combustor tuned the acoustics of the system to excite
instabilities over a range of operating conditions without a pilot flame. The inlet velocity was varied from 25 – 50 m/s and the equivalence ratio was varied from 0.525 – 0.65. This range of operating conditions was determined by the operating range of the
combustion test facility. Stability at each operating condition and combustor length was characterized by measurements of pressure oscillations in the combustor. The effect of the pilot flame on the magnitude and frequency of combustor stability was then investigated.
The mechanisms responsible for the pilot flame effect were studied using chemiluminescence flame images of both stable and unstable flames. Stable flame structure was investigated using stable flame images of CH* chemiluminescence emission. The effect of the pilot on stable flame metrics such as flame length, flame angle, and flame width was investigated. In addition, a new flame metric, flame base distance, was defined to characterize the effect of the pilot flame on stable flame anchoring of the flame base to the centerbody. The effect of the pilot flame on flame base anchoring was investigated because the improved stability with a pilot flame is usually attributed to improved flame anchoring through the recirculation of hot products from the pilot to the main flame base.
Chemiluminescence images of unstable flames were used to identify several instability mechanisms and infer how these mechanisms are affected by the pilot flame. Flame images of cases in which the pilot flame did not eliminate the instability were investigated to understand why the pilot flame is not effective in certain cases. The phase of unstable pilot flame oscillations was investigated to determine how the phase of pilot flame oscillations may affect its ability to interfere with instability mechanisms in the main flame.
A forced flame response study was conducted to determine the effect of inlet velocity oscillation amplitude on the pilot flame. The flame response was characterized by measurements of velocity oscillations in the injector and chemiluminescence intensity oscillations determined from flame images. As the forcing amplitude increases, the pilot flame’s effect on the flame transfer function magnitude becomes weaker. Flame images show that as the forcing amplitude increases, the pilot flame oscillations increase, leading to an ineffective pilot. The results of the…
Advisors/Committee Members: Domenic Adam Santavicca, Dissertation Advisor/Co-Advisor, Domenic Adam Santavicca, Committee Chair/Co-Chair, Domenic Adam Santavicca, Committee Member, Jacqueline Antonia O'connor, Committee Member, Richard A Yetter, Committee Member, Michael Matthew Micci, Committee Member.
Subjects/Keywords: Combustion; combustion dynamics; pilot flame; technically pre-mixed; self-excited instabilities
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APA ·
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Manager
APA (6th Edition):
O'meara, B. C. (2015). An experimental study of the effect of a pilot flame on technically pre-mixed, self-excited combustion instabilities. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/27285
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
O'meara, Bridget C. “An experimental study of the effect of a pilot flame on technically pre-mixed, self-excited combustion instabilities.” 2015. Thesis, Penn State University. Accessed February 28, 2021.
https://submit-etda.libraries.psu.edu/catalog/27285.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
O'meara, Bridget C. “An experimental study of the effect of a pilot flame on technically pre-mixed, self-excited combustion instabilities.” 2015. Web. 28 Feb 2021.
Vancouver:
O'meara BC. An experimental study of the effect of a pilot flame on technically pre-mixed, self-excited combustion instabilities. [Internet] [Thesis]. Penn State University; 2015. [cited 2021 Feb 28].
Available from: https://submit-etda.libraries.psu.edu/catalog/27285.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
O'meara BC. An experimental study of the effect of a pilot flame on technically pre-mixed, self-excited combustion instabilities. [Thesis]. Penn State University; 2015. Available from: https://submit-etda.libraries.psu.edu/catalog/27285
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Purdue University
7.
Tamanampudi, Gowtham Manikanta Reddy.
Reduced Order Modeling and Analysis of Combustion Instabilities.
Degree: MSin Aeronautics and Astronautics, Aeronautics and Astronautics, 2015, Purdue University
URL: https://docs.lib.purdue.edu/open_access_theses/1080
► The coupling between unsteady heat release and pressure fluctuations in a combustor leads to the complex phenomenon of combustion instability. Combustion instability can lead to…
(more)
▼ The coupling between unsteady heat release and pressure fluctuations in a combustor leads to the complex phenomenon of
combustion instability.
Combustion instability can lead to enormous pressure fluctuations and high rates of combustor heat transfer which play a very important role in determining the life and performance of engine. Although high fidelity simulations are starting to yield detailed understanding of the underlying physics of
combustion instability, the enormous computing power required restricts their application to a few runs and fairly simple geometries. To overcome this, low order models are being employed for prediction and analysis. Since low order models cannot account for the coupling between heat release and pressure fluctuations, lower-order
combustion response models are required. One such attempt is made through the work presented here using a commercial software COMSOL.
Advisors/Committee Members: WILLIAM E ANDERSON, TIMOTHEE L POURPOINT, JAMES C SISCO.
Subjects/Keywords: Combustion instabilities; Combustion response function; COMSOL; Linearized Euler equation; Transverse Instability
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APA (6th Edition):
Tamanampudi, G. M. R. (2015). Reduced Order Modeling and Analysis of Combustion Instabilities. (Thesis). Purdue University. Retrieved from https://docs.lib.purdue.edu/open_access_theses/1080
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Tamanampudi, Gowtham Manikanta Reddy. “Reduced Order Modeling and Analysis of Combustion Instabilities.” 2015. Thesis, Purdue University. Accessed February 28, 2021.
https://docs.lib.purdue.edu/open_access_theses/1080.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Tamanampudi, Gowtham Manikanta Reddy. “Reduced Order Modeling and Analysis of Combustion Instabilities.” 2015. Web. 28 Feb 2021.
Vancouver:
Tamanampudi GMR. Reduced Order Modeling and Analysis of Combustion Instabilities. [Internet] [Thesis]. Purdue University; 2015. [cited 2021 Feb 28].
Available from: https://docs.lib.purdue.edu/open_access_theses/1080.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Tamanampudi GMR. Reduced Order Modeling and Analysis of Combustion Instabilities. [Thesis]. Purdue University; 2015. Available from: https://docs.lib.purdue.edu/open_access_theses/1080
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
INP Toulouse
8.
Ghani, Abdulla.
Simulation aux grandes échelles des instabilités de combustion transverses des flammes parfaitement prémélangées et swirlées diphasiques : LES of self-excited transverse combustion instabilities in perfectly-premixed and swirling spray flames.
Degree: Docteur es, Dynamique des fluides, 2015, INP Toulouse
URL: http://www.theses.fr/2015INPT0068
► Dans cette thèse, les instabilités de combustion sont étudiées sur deux types de configuration. Tout d’abord, un cas académique stabilisé par un dièdre (Volvo) est…
(more)
▼ Dans cette thèse, les instabilités de combustion sont étudiées sur deux types de configuration. Tout d’abord, un cas académique stabilisé par un dièdre (Volvo) est étudié. Les simulations sont validées par comparaison avec les données expérimentales. En faisant varier le point de fonctionnement, des modes transverses et longitudinaux sont observés, en bon accord avec les données expérimentales en termes de fréquence des fluctuations de pression et de la dynamique de l’écoulement. Dans un second temps, une configuration proche des cas industriels a été étudiée dans le cadre du projet européen KIAI (Lotar). Les données expérimentales ont été obtenues lors d’une campagne d’essais à l’ONERA. Plusieurs simulations aux grandes échelles sont conduites sur cette configuration. Les instabilités transverses de combustion sont analysées et les mécanismes essentiels qui les pilotent sont identifiés. Sur la base de ces observations, la forme du modèle à Fonction de Transfert de Flamme est modifiée et associée à un solveur de Helmholtz pour prédire la stabilité des modes transverses. Les résultats obtenus par le solveur acoustique sont en bon accord avec la carte de stabilité obtenue par la simulation aux grandes échelles.
In this work longitudinal and transverse combustion instabilities are studied in two types of configurations. While longitudinal modes have been observed in many previous studies at low frequencies, the present work also focusses on high-frequency transverse modes. First, a premixed flame stabilized on a V-fame holder is investigated where experimental results obtained by Volvo are used to validate the simulations. For different operating conditions, longitudinal and transverse modes are observed in Large Eddy Simulations (LES) and show good agreement with the experimental data in terms of pressure frequency and flow dynamics. In a second step, a semi-industrial case is examined within the European project KIAI. Experiments are conducted by ONERA and LES of this two-phase flow configuration (called Lotar) are carried out. Transverse combustion instabilities are analyzed and key elements which drive instabilities are identied. These observations are used to reformulate the classic Flame Transfer Function (FTF) in order to predict the stability of transverse modes by use of an Helmholtz solver. The results reproduce fairly well the stability map generated by LES.
Advisors/Committee Members: Gicquel, Laurent (thesis director).
Subjects/Keywords: Mode transverse; Instabilités de combustion; Transverse modes; Combustion instabilities
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APA ·
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APA (6th Edition):
Ghani, A. (2015). Simulation aux grandes échelles des instabilités de combustion transverses des flammes parfaitement prémélangées et swirlées diphasiques : LES of self-excited transverse combustion instabilities in perfectly-premixed and swirling spray flames. (Doctoral Dissertation). INP Toulouse. Retrieved from http://www.theses.fr/2015INPT0068
Chicago Manual of Style (16th Edition):
Ghani, Abdulla. “Simulation aux grandes échelles des instabilités de combustion transverses des flammes parfaitement prémélangées et swirlées diphasiques : LES of self-excited transverse combustion instabilities in perfectly-premixed and swirling spray flames.” 2015. Doctoral Dissertation, INP Toulouse. Accessed February 28, 2021.
http://www.theses.fr/2015INPT0068.
MLA Handbook (7th Edition):
Ghani, Abdulla. “Simulation aux grandes échelles des instabilités de combustion transverses des flammes parfaitement prémélangées et swirlées diphasiques : LES of self-excited transverse combustion instabilities in perfectly-premixed and swirling spray flames.” 2015. Web. 28 Feb 2021.
Vancouver:
Ghani A. Simulation aux grandes échelles des instabilités de combustion transverses des flammes parfaitement prémélangées et swirlées diphasiques : LES of self-excited transverse combustion instabilities in perfectly-premixed and swirling spray flames. [Internet] [Doctoral dissertation]. INP Toulouse; 2015. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2015INPT0068.
Council of Science Editors:
Ghani A. Simulation aux grandes échelles des instabilités de combustion transverses des flammes parfaitement prémélangées et swirlées diphasiques : LES of self-excited transverse combustion instabilities in perfectly-premixed and swirling spray flames. [Doctoral Dissertation]. INP Toulouse; 2015. Available from: http://www.theses.fr/2015INPT0068
9.
Ndiaye, Aïssatou.
Uncertainty Quantification of Thermo-acousticinstabilities in gas turbine combustors : Quantification des incertitudes pour la prédiction des instabilités thermo-acoustiques dans les chambres de combustion.
Degree: Docteur es, Mathématiques et modélisation, 2017, Montpellier
URL: http://www.theses.fr/2017MONTS062
► Les instabilités thermo-acoustiques résultent de l'interaction entre les oscillations de pression acoustique et les fluctuations du taux de dégagement de chaleur de la flamme. Ces…
(more)
▼ Les instabilités thermo-acoustiques résultent de l'interaction entre les oscillations de pression acoustique et les fluctuations du taux de dégagement de chaleur de la flamme. Ces instabilités de
combustion sont particulièrement préoccupantes en raison de leur fréquence dans les turbines à gaz modernes et à faible émission. Leurs principaux effets indésirables sont une réduction du temps de fonctionnement du moteur en raison des oscillations de grandes amplitudes ainsi que de fortes vibrations à l'intérieur de la chambre de
combustion. La simulation numérique est maintenant devenue une approche clé pour comprendre et prédire ces instabilités dans la phase de conception industrielle. Cependant, la prédiction de ce phénomène reste difficile en raison de sa complexité; cela se confirme lorsque les paramètres physiques du processus de modélisation sont incertains, ce qui est pratiquement toujours le cas pour des systèmes réels.Introduire la quantification des incertitudes pour la thermo-acoustique est le seul moyen d'étudier et de contrôler la stabilité des chambres de
combustion qui fonctionnent dans des conditions réalistes; c'est l'objectif de cette thèse.Dans un premier temps, une chambre de
combustion académique (avec un seul injecteur et une seule flamme) ainsi que deux chambres de moteurs d'hélicoptère (avec N injecteurs et des flammes) sont étudiés. Les calculs basés sur un solveur de Helmholtz et un outil quasi-analytique de bas ordre fournissent des estimations appropriées de la fréquence et des structures modales pour chaque géométrie. L'analyse suggère que la réponse de la flamme aux perturbations acoustiques joue un rôle prédominant dans la dynamique de la chambre de
combustion. Ainsi, la prise en compte des incertitudes liées à la représentation de la flamme apparaît comme une étape nécessaire vers une analyse robuste de la stabilité du système.Dans un second temps, la notion de facteur de risque, c'est-à-dire la probabilité pour un mode thermo-acoustique d'être instable, est introduite afin de fournir une description plus générale du système que la classification classique et binaire (stable / instable). Les approches de modélisation de Monte Carlo et de modèle de substitution sont associées pour effectuer une analyse de quantification d'incertitudes de la chambre de
combustion académique avec deux paramètres incertains (amplitude et temps de réponse de la flamme). On montre que l'utilisation de modèles de substitution algébriques réduit drastiquement le nombre de calculs initiales, donc la charge de calcul, tout en fournissant des estimations précises du facteur de risque modal. Pour traiter les problèmes multidimensionnel tels que les deux moteurs d'hélicoptère, une stratégie visant à réduire le nombre de paramètres incertains est introduite. La méthode <<Active Subspace>> combinée à une approche de changement de variables a permis d'identifier trois directions dominantes (au lieu des N paramètres incertains initiaux) qui suffisent à décrire la dynamique des deux systèmes industriels. Dès lors que ces…
Advisors/Committee Members: Nicoud, Franck (thesis director).
Subjects/Keywords: Quantification d'incertitudes; Combustion; Instabilités Thermoacoustique; Combustion; Uncertainty quantification; Thermoacoustic Instabilities
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APA ·
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APA (6th Edition):
Ndiaye, A. (2017). Uncertainty Quantification of Thermo-acousticinstabilities in gas turbine combustors : Quantification des incertitudes pour la prédiction des instabilités thermo-acoustiques dans les chambres de combustion. (Doctoral Dissertation). Montpellier. Retrieved from http://www.theses.fr/2017MONTS062
Chicago Manual of Style (16th Edition):
Ndiaye, Aïssatou. “Uncertainty Quantification of Thermo-acousticinstabilities in gas turbine combustors : Quantification des incertitudes pour la prédiction des instabilités thermo-acoustiques dans les chambres de combustion.” 2017. Doctoral Dissertation, Montpellier. Accessed February 28, 2021.
http://www.theses.fr/2017MONTS062.
MLA Handbook (7th Edition):
Ndiaye, Aïssatou. “Uncertainty Quantification of Thermo-acousticinstabilities in gas turbine combustors : Quantification des incertitudes pour la prédiction des instabilités thermo-acoustiques dans les chambres de combustion.” 2017. Web. 28 Feb 2021.
Vancouver:
Ndiaye A. Uncertainty Quantification of Thermo-acousticinstabilities in gas turbine combustors : Quantification des incertitudes pour la prédiction des instabilités thermo-acoustiques dans les chambres de combustion. [Internet] [Doctoral dissertation]. Montpellier; 2017. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2017MONTS062.
Council of Science Editors:
Ndiaye A. Uncertainty Quantification of Thermo-acousticinstabilities in gas turbine combustors : Quantification des incertitudes pour la prédiction des instabilités thermo-acoustiques dans les chambres de combustion. [Doctoral Dissertation]. Montpellier; 2017. Available from: http://www.theses.fr/2017MONTS062
10.
Prieur, Kevin.
Dynamique de la combustion dans un foyer annulaire multi-injecteurs diphasique : Combustion dynamics of an annular combustor with multiple spray injectors.
Degree: Docteur es, Combustion, 2017, Université Paris-Saclay (ComUE)
URL: http://www.theses.fr/2017SACLC070
► Ces dernières décennies ont vu apparaître de nombreuses innovations dans le domaine de la combustion afin de réduire la consommation et les émissions polluantes. De…
(more)
▼ Ces dernières décennies ont vu apparaître de nombreuses innovations dans le domaine de la combustion afin de réduire la consommation et les émissions polluantes. De nouveaux types d'injecteur, de type LPP - Lean Premixed Prevaporized, ont été mis au point permettant de diminuer le rapport combustible/air et visent à pré-vaporiser le carburant en amont de la combustion afin de mieux le mélanger à l'air issu du compresseur. Cette architecture permet une amélioration de la consommation et des émissions polluantes, mais rend les foyers annulaires plus sensibles à des phénomènes instationnaires qui perturbent le fonctionnement du système, accroissent les flux de chaleur vers les parois de la chambre, induisent des vibrations de structures, entrainent une fatigue cyclique des pièces mécaniques et dans des cas extrêmes conduisent à des dommages irréversibles. L'objectif est de poursuivre l'effort engagé au laboratoire EM2C sur ce thème et plus particulièrement sur celui de la dynamique de la combustion dans les chambres annulaires. La thèse concerne plus spécialement le cas où l'injection du combustible s'effectue sous forme liquide. La configuration reproduit sous forme idéalisée celle que l'on trouve en pratique dans les moteurs aéronautiques. La chambre, désignée sous le nom de MICCA-Spray, est équipée de 16 injecteurs swirlés pouvant être alimentés par un combustible liquide ou gazeux, permettant ainsi une combustion diphasique ou prémélangée. Le système possède des parois en quartz donnant un accès optique à la zone de flamme. Il est aussi équipé d'un ensemble de diagnostics tels des microphones, des photomultiplicateurs ainsi que des systèmes d'imagerie à haute cadence.
These last decades have seen many innovations in the field of combustion to reduce fuel consumption and pollutant emissions. New types of injector, for example LPP - Lean Premixed Prevaporized, have then been developed to reduce the fuel / air ratio and aim to pre-vaporize the fuel upstream of the combustion in order to mix it better with the air coming from the compressor. Unfortunately this architecture makes annular chambers more sensitive to unsteady phenomena which disturb the functioning of the system, increase the heat flows towards the walls of the chamber, induce vibrations of structures, cause cyclic fatigue of mechanical parts and in extreme cases lead to irreversible damage. The objective of this thesis is to continue the effort undertaken at the EM2C laboratory on this topic and more particularly on the dynamics of combustion in annular chambers comprising a set of injectors. The thesis concerns more particularly the case where the injection of the fuel takes place in liquid form. This configuration reproduces, in idealized form, what can be found in practice in aeronautical engines. It is also a configuration studied at the fundamental level. The chamber, known as MICCA-Spray, is equipped with 16 swirled injectors that can be powered by liquid or gaseous fuel, thus enabling two-phase or fully premixed combustion. The system has quartz…
Advisors/Committee Members: Schuller, Thierry (thesis director), Candel, Sébastien (thesis director), Durox, Daniel (thesis director).
Subjects/Keywords: Dynamique de la combustion; Instabilités de combustion; Chambre annulaire; Allumage; Combustion dynamics; Combustion instabilities; Annular chamber; Light-round
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APA (6th Edition):
Prieur, K. (2017). Dynamique de la combustion dans un foyer annulaire multi-injecteurs diphasique : Combustion dynamics of an annular combustor with multiple spray injectors. (Doctoral Dissertation). Université Paris-Saclay (ComUE). Retrieved from http://www.theses.fr/2017SACLC070
Chicago Manual of Style (16th Edition):
Prieur, Kevin. “Dynamique de la combustion dans un foyer annulaire multi-injecteurs diphasique : Combustion dynamics of an annular combustor with multiple spray injectors.” 2017. Doctoral Dissertation, Université Paris-Saclay (ComUE). Accessed February 28, 2021.
http://www.theses.fr/2017SACLC070.
MLA Handbook (7th Edition):
Prieur, Kevin. “Dynamique de la combustion dans un foyer annulaire multi-injecteurs diphasique : Combustion dynamics of an annular combustor with multiple spray injectors.” 2017. Web. 28 Feb 2021.
Vancouver:
Prieur K. Dynamique de la combustion dans un foyer annulaire multi-injecteurs diphasique : Combustion dynamics of an annular combustor with multiple spray injectors. [Internet] [Doctoral dissertation]. Université Paris-Saclay (ComUE); 2017. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2017SACLC070.
Council of Science Editors:
Prieur K. Dynamique de la combustion dans un foyer annulaire multi-injecteurs diphasique : Combustion dynamics of an annular combustor with multiple spray injectors. [Doctoral Dissertation]. Université Paris-Saclay (ComUE); 2017. Available from: http://www.theses.fr/2017SACLC070
11.
Boudy, Frédéric.
Analyse de la dynamique non-linéaire et du contrôle des instabilités de combustion fondée sur la "Flame Describing Function" (FDF) : Nonlinear dynamics and control analysis of combustion instabilities based on the “Flame Describing Function” (FDF).
Degree: Docteur es, Energétique, 2012, Châtenay-Malabry, Ecole centrale de Paris
URL: http://www.theses.fr/2012ECAP0056
► Cette thèse se concentre sur l’étude des instabilités de combustion dans un brûleur prémélangé. Les instabilités sont généralement issues d’un couplage entre la combustion et…
(more)
▼ Cette thèse se concentre sur l’étude des instabilités de
combustion dans un brûleur prémélangé. Les instabilités sont généralement issues d’un couplage entre la
combustion et les modes propres du système. La mise en résonance qui en résulte peut avoir des conséquences qui sont souvent dommageables, entraînant des vibrations, une fatigue des matériaux soumis à des charges acoustiques élevées et une intensification des flux de chaleur vers les parois de la chambre. Un premier objectif de cette thèse est de poursuivre le développement de méthodes de prévision des instabilités et des phénomènes non-linéaires qui en résultent comme par exemple le développement de cycles limites, les processus de déclenchement (“triggering”), la commutation de modes. Le cadre général adopté est celui de «°l’équivalent harmonique » bien connu dans le domaine du contrôle et qui a été exploré dans le domaine des instabilités de
combustion dans des travaux récents du laboratoire EM2C, CNRS. Par le biais de ce concept il est possible de tenir compte de l’´evolution de la réponse de la flamme suivant l’amplitude à laquelle elle est soumise. Cette réponse de flamme en fréquence et amplitude généralise la notion de fonction de transfert et elle est désignée sous le nom de “Flame Describing Function” (FDF). Le système est ouvert à son extrémité aval. Cette géométrie permet de simplifier l’analyse et d’obtenir une large gamme de configurations au moyen d’une variation continue de la longueur du conduit d’alimentation qui est limité en amont par un piston. On peut aussi échanger le tube à flamme et utiliser des longueurs différentes de cet élément. Une étude exhaustive est réalisée pour répertorier les oscillations observées et déduire leurs propriétés. On montre que les cycles limites qui possèdent une amplitude constante sont bien décrits par la méthode unifiée fondée sur la FDF. Pour certaines configurations l’expérience fait apparaître des cycles limites dont l’amplitude et la fréquence ne se stabilisent pas au cours du temps. On observe notamment des oscillations plus complexes couplées par plusieurs modes pouvant soit donner lieu à des variations régulières ou à des fluctuations plus irrégulières avec un caractère “galopant” dans le temps. Pour ces oscillations particulières, la FDF fournit des indications sur les domaines d’apparition mais n’est pas en mesure de décrire complètement ces cycles limites complexes. Il faut dans ce cas recourir à une représentation temporelle qui n’est pas développée dans ce document. La base de données expérimentales pourra être utilisée pour guider ultérieurement ce type d’analyse. Le deuxième grand objectif de cette thèse est de rechercher des méthodes de contrôle des instabilités. On considère plus particulièrement des systèmes dynamiques utilisant des plaques perforées polarisées par un écoulement (BFP : “bias flow perforate”). Ces systèmes sont particulièrement intéressants pour atténuer les oscillations basse fréquence qui sont difficiles à réduire par des systèmes passifs. La conception de ces BFPs est…
Advisors/Committee Members: Candel, Sébastien (thesis director).
Subjects/Keywords: Instabilités de combustion; Couplage thermoacoustique; Cycle limite stable; Combustion instabilities; Thermoacoustic coupling; Flame Describing Function
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APA ·
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MLA ·
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CSE |
Export
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APA (6th Edition):
Boudy, F. (2012). Analyse de la dynamique non-linéaire et du contrôle des instabilités de combustion fondée sur la "Flame Describing Function" (FDF) : Nonlinear dynamics and control analysis of combustion instabilities based on the “Flame Describing Function” (FDF). (Doctoral Dissertation). Châtenay-Malabry, Ecole centrale de Paris. Retrieved from http://www.theses.fr/2012ECAP0056
Chicago Manual of Style (16th Edition):
Boudy, Frédéric. “Analyse de la dynamique non-linéaire et du contrôle des instabilités de combustion fondée sur la "Flame Describing Function" (FDF) : Nonlinear dynamics and control analysis of combustion instabilities based on the “Flame Describing Function” (FDF).” 2012. Doctoral Dissertation, Châtenay-Malabry, Ecole centrale de Paris. Accessed February 28, 2021.
http://www.theses.fr/2012ECAP0056.
MLA Handbook (7th Edition):
Boudy, Frédéric. “Analyse de la dynamique non-linéaire et du contrôle des instabilités de combustion fondée sur la "Flame Describing Function" (FDF) : Nonlinear dynamics and control analysis of combustion instabilities based on the “Flame Describing Function” (FDF).” 2012. Web. 28 Feb 2021.
Vancouver:
Boudy F. Analyse de la dynamique non-linéaire et du contrôle des instabilités de combustion fondée sur la "Flame Describing Function" (FDF) : Nonlinear dynamics and control analysis of combustion instabilities based on the “Flame Describing Function” (FDF). [Internet] [Doctoral dissertation]. Châtenay-Malabry, Ecole centrale de Paris; 2012. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2012ECAP0056.
Council of Science Editors:
Boudy F. Analyse de la dynamique non-linéaire et du contrôle des instabilités de combustion fondée sur la "Flame Describing Function" (FDF) : Nonlinear dynamics and control analysis of combustion instabilities based on the “Flame Describing Function” (FDF). [Doctoral Dissertation]. Châtenay-Malabry, Ecole centrale de Paris; 2012. Available from: http://www.theses.fr/2012ECAP0056
12.
Tran, Nicolas.
Influence de la condition limite acoustique amont sur les instabilités de combustion de grande amplitude : conception d’un système robuste de contrôle d’impédance : Influence of inlet acoustic boundary condition on large amplitude combustion instabilities : design of a robust impedance control system.
Degree: Docteur es, Energétique, 2009, Châtenay-Malabry, Ecole centrale de Paris
URL: http://www.theses.fr/2009ECAP0013
► Les contraintes économiques, environnementales et sociétales de ces vingt dernières années notamment dans les domaines de l’énergie et des transports ont débouché sur le développement…
(more)
▼ Les contraintes économiques, environnementales et sociétales de ces vingt dernières années notamment dans les domaines de l’énergie et des transports ont débouché sur le développement de nouvelles technologies faisant intervenir la
combustion pauvre et prémélangée. Ce mode de
combustion à partir d'un mélange homogène conduit à des températures de flamme plus faibles qui permettent de réduire les émissions d'oxydes d'azote tout en limitant la production d'oxydes de carbone. Pour autant, la
combustion pauvre prémélangée présente le désavantage d’être sensible à toute forme de couplage notamment acoustique, menant à des instabilités de
combustion. Ces instabilités sont largement étudiées, mais restent très difficiles à prévoir car elles font intervenir de nombreux phénomènes physiques multi-échelles. Dans la plupart des cas les oscillations résultent d’un couplage résonant entre la dynamique de la
combustion et l’acoustique du système. Les conditions aux limites acoustiques du système déterminent la structure du champ de pression dans l’installation, ainsi que les flux acoustiques entrants et sortants. Malgré son importance, l’influence des conditions aux limites n’est pas toujours bien comprise et prise en compte et elle ne fait pas l’objet d’études systématiques. Les conditions aux limites acoustiques ne sont pas faciles à déterminer expérimentalement sur des configurations pratiques et leur contrôle est rarement envisagé. L’objectif de ce travail est donc de répondre à ce manque d’information, en étudiant sur un banc de
combustion turbulente (CTRL-Z) l’influence de la condition acoustique d’entrée sur les oscillations de
combustion auto-entretenues qui apparaissent dans la chambre de
combustion. Un système de contrôle a été développé pour piloter l’impédance du système de prémélange de façon passive, sans modification des conditions de fonctionnement ou de la géométrie du brûleur. Ce système de contrôle d’impédance (ICS, « Impedance Control System ») s’appuie sur une utilisation de plaques perforées faiblement poreuses, au travers desquelles circule un écoulement. Un piston mobile permet de piloter la profondeur de la cavité résonante formée en amont des plaques, et ainsi de piloter leurs impédances. L’impédance de ces plaques perforées a été étudiée pour de faibles et de forts niveaux d’excitation acoustique, et un critère de transition entre les régimes linéaire et non-linéaire a été déterminé. L’ICS a été optimisé pour permettre un contrôle du module du coefficient de réflexion de 0 à 1 sur une large plage de fréquences (100 à 1000 Hz) et de niveaux d’amplitude de perturbations (100 à 150 dB) couvrant ainsi la gamme des instabilités thermoacoustiques classiques. L’ICS est utilisé pour contrôler l’impédance d’entrée du système de prémélange du banc CTRL-Z, en regard de la zone de
combustion. L’analyse spectrale des fluctuations de pression et de dégagement de chaleur en fonction de l’impédance d’entrée démontre qu’il est possible d’obtenir un amortissement de l’instabilité principale pouvant atteindre 20 dB. Ces…
Advisors/Committee Members: Candel, Sébastien (thesis director).
Subjects/Keywords: Combustion; Acoustique; Instabilités thermoacoustiques; Contrôle Passif; Plaques Perforées; Combustion; Thermo-acoustic instabilities; Passive Control
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APA (6th Edition):
Tran, N. (2009). Influence de la condition limite acoustique amont sur les instabilités de combustion de grande amplitude : conception d’un système robuste de contrôle d’impédance : Influence of inlet acoustic boundary condition on large amplitude combustion instabilities : design of a robust impedance control system. (Doctoral Dissertation). Châtenay-Malabry, Ecole centrale de Paris. Retrieved from http://www.theses.fr/2009ECAP0013
Chicago Manual of Style (16th Edition):
Tran, Nicolas. “Influence de la condition limite acoustique amont sur les instabilités de combustion de grande amplitude : conception d’un système robuste de contrôle d’impédance : Influence of inlet acoustic boundary condition on large amplitude combustion instabilities : design of a robust impedance control system.” 2009. Doctoral Dissertation, Châtenay-Malabry, Ecole centrale de Paris. Accessed February 28, 2021.
http://www.theses.fr/2009ECAP0013.
MLA Handbook (7th Edition):
Tran, Nicolas. “Influence de la condition limite acoustique amont sur les instabilités de combustion de grande amplitude : conception d’un système robuste de contrôle d’impédance : Influence of inlet acoustic boundary condition on large amplitude combustion instabilities : design of a robust impedance control system.” 2009. Web. 28 Feb 2021.
Vancouver:
Tran N. Influence de la condition limite acoustique amont sur les instabilités de combustion de grande amplitude : conception d’un système robuste de contrôle d’impédance : Influence of inlet acoustic boundary condition on large amplitude combustion instabilities : design of a robust impedance control system. [Internet] [Doctoral dissertation]. Châtenay-Malabry, Ecole centrale de Paris; 2009. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2009ECAP0013.
Council of Science Editors:
Tran N. Influence de la condition limite acoustique amont sur les instabilités de combustion de grande amplitude : conception d’un système robuste de contrôle d’impédance : Influence of inlet acoustic boundary condition on large amplitude combustion instabilities : design of a robust impedance control system. [Doctoral Dissertation]. Châtenay-Malabry, Ecole centrale de Paris; 2009. Available from: http://www.theses.fr/2009ECAP0013
INP Toulouse
13.
Dupuy, Fabien.
Reduced Order Models and Large Eddy Simulation for Combustion Instabilities in aeronautical Gas Turbines : Modèles réduits et Simulations aux Grandes Echelles pour les instabilités thermoacoustiques dans les turbines à gaz aéronautiques.
Degree: Docteur es, Energétique et Transferts, 2020, INP Toulouse
URL: http://www.theses.fr/2020INPT0046
► Des réglementations de plus en plus strictes et un intérêt environnemental grandissant ont poussé les constructeurs de moteurs aéronautiques à développer la génération actuelle de…
(more)
▼ Des réglementations de plus en plus strictes et un intérêt environnemental grandissant ont poussé les constructeurs de moteurs aéronautiques à développer la génération actuelle de chambres de
combustion, affichant des consommations et émissions de polluants plus basses que jamais. Cependant, les phases de conception de chambres modernes ont clairement mis en évidence que celles-ci sont plus susceptibles de développer des instabilités de
combustion, où le couplage entre l'acoustique de la chambre et la flamme suscite de larges oscillations de pression ainsi que des vibrations de la structure. Ces instabilités peuvent endommager le moteur, et potentiellement entraîner sa destruction. Dans le même temps, de considérables avancées ont eu lieu dans le domaine de la simulation numérique, et la Mécanique des Fluides Numérique (MFN) a démontré sa capacité à reproduire la dynamique de flammes instationnaires et les instabilités de
combustion observées dans les moteurs. Pourtant, même avec le matériel informatique moderne, le temps de calcul reste la contrainte clé de ces simulations haute-fidélité, qui demeurent très coûteuses. Typiquement, couvrir la totalité du domaine de fonctionnement pour un moteur industriel est encore hors de portée. Des modèles dits bas-ordre existent également, et prédire efficacement les instabilités de
combustion par leur intermédiaire est envisageable à la condition d'une modélisation appropriée de l'interaction entre l'acoustique et la flamme. La méthode de modélisation la plus commune de cet élément critique est la fonction de transfert de flamme (FTF) qui lie les fluctuations de taux de dégagement de chaleur aux fluctuations de vitesse en un point donné. Cette fonction de transfert peut être obtenue à partir de modèles analytiques, mais très peu existent pour des flammes swirlées turbulentes. Une autre approche consiste à réaliser des mesures expérimentales ou des simulations haute fidélité coûteuses, réduisant à néant la capacité de prédiction rapide recherchée avec les méthodes bas-ordre. Cette thèse vise donc à développer des outils bas ordre à la fois rapides et fiables pour la modélisation des instabilités de
combustion, ainsi qu'à améliorer la compréhension des mécanismes inhérents à la réponse acoustique d'une flamme swirlée. A cet effet, une approche hybride nouvelle est proposée, où un nombre réduit de simulations haute fidélité peut être utilisé pour déterminer les paramètres d'entrée d'un modèle analytique représentatif de la fonction de transfert d'une flamme swirlée prémélangée. Le modèle analytique s'appuie sur des travaux antérieurs traitant la flamme comme une interface perturbée, et prend en compte la conversion acoustique-vorticité à travers un swirler. La validité du modèle est mise à l'épreuve en déterminant les divers paramètres nécessaires associés à partir de simulations numériques réactives stationnaires et pulsées d'une flamme prémélangée swirlée académique. Il est également démontré que le modèle peut prendre en compte diverses amplitudes de perturbation. Enfin, des…
Advisors/Committee Members: Poinsot, Thierry (thesis director), Gicquel, Laurent (thesis director).
Subjects/Keywords: Combustion; Instabilités; Simulation numérique; Acoustique; Turbine à gaz; Combustion; Instabilities; Numerical simulation; Acoustics; Gas turbine
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APA (6th Edition):
Dupuy, F. (2020). Reduced Order Models and Large Eddy Simulation for Combustion Instabilities in aeronautical Gas Turbines : Modèles réduits et Simulations aux Grandes Echelles pour les instabilités thermoacoustiques dans les turbines à gaz aéronautiques. (Doctoral Dissertation). INP Toulouse. Retrieved from http://www.theses.fr/2020INPT0046
Chicago Manual of Style (16th Edition):
Dupuy, Fabien. “Reduced Order Models and Large Eddy Simulation for Combustion Instabilities in aeronautical Gas Turbines : Modèles réduits et Simulations aux Grandes Echelles pour les instabilités thermoacoustiques dans les turbines à gaz aéronautiques.” 2020. Doctoral Dissertation, INP Toulouse. Accessed February 28, 2021.
http://www.theses.fr/2020INPT0046.
MLA Handbook (7th Edition):
Dupuy, Fabien. “Reduced Order Models and Large Eddy Simulation for Combustion Instabilities in aeronautical Gas Turbines : Modèles réduits et Simulations aux Grandes Echelles pour les instabilités thermoacoustiques dans les turbines à gaz aéronautiques.” 2020. Web. 28 Feb 2021.
Vancouver:
Dupuy F. Reduced Order Models and Large Eddy Simulation for Combustion Instabilities in aeronautical Gas Turbines : Modèles réduits et Simulations aux Grandes Echelles pour les instabilités thermoacoustiques dans les turbines à gaz aéronautiques. [Internet] [Doctoral dissertation]. INP Toulouse; 2020. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2020INPT0046.
Council of Science Editors:
Dupuy F. Reduced Order Models and Large Eddy Simulation for Combustion Instabilities in aeronautical Gas Turbines : Modèles réduits et Simulations aux Grandes Echelles pour les instabilités thermoacoustiques dans les turbines à gaz aéronautiques. [Doctoral Dissertation]. INP Toulouse; 2020. Available from: http://www.theses.fr/2020INPT0046
University of Cincinnati
14.
Estefanos, Wessam.
Effects of the Fuel-Air Mixing on Combustion Instabilities
and NOx Emissions in Lean Premixed Combustion.
Degree: PhD, Engineering and Applied Science: Aerospace
Engineering, 2016, University of Cincinnati
URL: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1460731723
► An experimental study was conducted to investigate the effects of the fuel-air mixing on combustion instabilities and NO<i>x</i> emissions in lean premixed combustion. High speed…
(more)
▼ An experimental study was conducted to investigate the
effects of the fuel-air mixing on
combustion instabilities and
NO<i>x</i> emissions in lean premixed
combustion. High
speed PIV measurements in water were conducted to capture the mean
and dynamic behavior of the cold flow generated by a 3X model of
the tested premixer. High speed PLIF in water measurements were
conducted to quantify the mean and unsteady fuel-air mixing at
different momentum flux ratios. Atmospheric
combustion tests using
the original premixer, were conducted using natural gas and propane
at the same momentum flux ratios of the PLIF mixing tests. An
emissions analyzer was used to measure the emissions from
combustion tests. Dynamic pressure transducers were used to measure
the amplitude and the frequency of the dynamic pressure
oscillations associated with the
combustion instabilities.
CHEMKIN-PRO was used to model the atmospheric
combustion and
predict NO<i>x</i> emissions at different conditions.
Results showed that unsteady fuel-air mixing was concentrated at
the center and near the outer edges of the premixer. These regions
were characterized by high fuel concentration gradients. With the
increase in the momentum flux ratio, the concentration gradient and
the level of unsteady mixing increased, indicating that the
fuel-air spatial unmixedness was the source of the unsteady mixing.
It was found that local flow turbulence tended to decrease the
concentration gradient through enhancing the fuel-air mixing, which
resulted in decreasing the level of unsteady mixing.
NO<i>x</i> emissions from atmospheric
combustion
increased with the increase in the momentum flux ratio due to the
increase in the flame temperature and the fuel-air spatial and
temporal unmixedness. The intensity of the
combustion dynamics
increased with the increase in the level of unsteady mixing. Axial
injection of the fuel into the regions of strong unsteady mixing
eliminated the
combustion dynamics through damping the unsteady
mixing. Results of CHEMKIN-PRO agreed very well with the
experimental results and showed that the spatial and temporal
unmixedness have a significant effect on NO<i>x</i>
emissions for very lean
combustion (F = 0.4). With the increase in
the equivalence ratio, their relative contribution
decreased.
Advisors/Committee Members: Jeng, San-Mou (Committee Chair).
Subjects/Keywords: Engineering; Lean premixed combustion; Fuel-air mixing; NOx emissions; Combustion instabilities; Unsteady flow behavior
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APA (6th Edition):
Estefanos, W. (2016). Effects of the Fuel-Air Mixing on Combustion Instabilities
and NOx Emissions in Lean Premixed Combustion. (Doctoral Dissertation). University of Cincinnati. Retrieved from http://rave.ohiolink.edu/etdc/view?acc_num=ucin1460731723
Chicago Manual of Style (16th Edition):
Estefanos, Wessam. “Effects of the Fuel-Air Mixing on Combustion Instabilities
and NOx Emissions in Lean Premixed Combustion.” 2016. Doctoral Dissertation, University of Cincinnati. Accessed February 28, 2021.
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1460731723.
MLA Handbook (7th Edition):
Estefanos, Wessam. “Effects of the Fuel-Air Mixing on Combustion Instabilities
and NOx Emissions in Lean Premixed Combustion.” 2016. Web. 28 Feb 2021.
Vancouver:
Estefanos W. Effects of the Fuel-Air Mixing on Combustion Instabilities
and NOx Emissions in Lean Premixed Combustion. [Internet] [Doctoral dissertation]. University of Cincinnati; 2016. [cited 2021 Feb 28].
Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1460731723.
Council of Science Editors:
Estefanos W. Effects of the Fuel-Air Mixing on Combustion Instabilities
and NOx Emissions in Lean Premixed Combustion. [Doctoral Dissertation]. University of Cincinnati; 2016. Available from: http://rave.ohiolink.edu/etdc/view?acc_num=ucin1460731723
Penn State University
15.
Orawannukul, Poravee.
An experimental study of forced flame response in technically premixed flame in a lean premixed gas turbine combustor.
Degree: 2014, Penn State University
URL: https://submit-etda.libraries.psu.edu/catalog/20795
► Flame response in a technically premixed, swirl-stabilized, turbulent, lean-premixed natural gas-air flame is investigated in a single research gas turbine injector. The main purpose of…
(more)
▼ Flame response in a technically premixed, swirl-stabilized, turbulent, lean-premixed natural gas-air flame is investigated in a single research gas turbine injector. The main purpose of this research is to understand flame behavior in the context of
combustion instabilities under technically premixed conditions, which is characteristic of industrial operation. In this operating mode, flames are exposed to both velocity and equivalence ratio fluctuations. Previous studies focused on heat release rate fluctuations due to velocity fluctuations, typically using CH* chemiluminescence emission as an indicator of heat release rate. However, chemiluminescence emission can only be used to measure heat release rate fluctuations in the presence of velocity fluctuations or equivalence ratio fluctuations, not both. Therefore two important questions need to be addressed. First, how does a flame respond to equivalence ratio fluctuations? Second, how can heat release rate fluctuations be measured in technically premixed flames?
Flame response to equivalence ratio fluctuations is studied with operating conditions similar to industrial gas turbine conditions, with the exception of combustor pressure. The response is primarily due to a convective mechanism. Fuel flow rate fluctuations produce equivalence ratio fluctuations at the fuel injection location and then travel through the injector and arrive at the flame with the mean flow. The flame response decreases with increasing frequency (Strouhal number).
A previously proposed "reconstruction technique" is experimentally validated and applied to measure heat release rate fluctuations in technically premixed flames. The heat release rate fluctuations in technically premixed flames are a vector superposition of the heat release rate fluctuations due to velocity fluctuations and heat release rate fluctuations due to equivalence ratio fluctuations. This technique assumes that the flame’s response to velocity fluctuations and equivalence fluctuations are both linear and independent. Since there is no independent measurement of heat release rate fluctuations in technically premixed flames that can be used to validate the reconstruction technique, the technique is indirectly validated over a range of operating conditions using chemiluminescence intensity fluctuation measurements. It was found that this technique is valid in both global and local measurements. The accuracy is within 20% in amplitude and 10o in phase. Strouhal number has the greatest contribution to the accuracy.
Flame response in technically premixed flames is measured. Flame transfer functions in technically premixed flames are the result of the constructive and destructive interactions between the flame’s response to velocity and equivalence ratio fluctuations, and depend on both the relative amplitude and phase of these contributions.
Advisors/Committee Members: Domenic Adam Santavicca, Dissertation Advisor/Co-Advisor, Thomas Litzinger, Committee Member, Richard A Yetter, Committee Member, Sarma V Pisupati, Committee Member.
Subjects/Keywords: Forced flame response; technically premixed flames; combustion instabilities; flame transfer function
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APA (6th Edition):
Orawannukul, P. (2014). An experimental study of forced flame response in technically premixed flame in a lean premixed gas turbine combustor. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/20795
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Orawannukul, Poravee. “An experimental study of forced flame response in technically premixed flame in a lean premixed gas turbine combustor.” 2014. Thesis, Penn State University. Accessed February 28, 2021.
https://submit-etda.libraries.psu.edu/catalog/20795.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Orawannukul, Poravee. “An experimental study of forced flame response in technically premixed flame in a lean premixed gas turbine combustor.” 2014. Web. 28 Feb 2021.
Vancouver:
Orawannukul P. An experimental study of forced flame response in technically premixed flame in a lean premixed gas turbine combustor. [Internet] [Thesis]. Penn State University; 2014. [cited 2021 Feb 28].
Available from: https://submit-etda.libraries.psu.edu/catalog/20795.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Orawannukul P. An experimental study of forced flame response in technically premixed flame in a lean premixed gas turbine combustor. [Thesis]. Penn State University; 2014. Available from: https://submit-etda.libraries.psu.edu/catalog/20795
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Virginia Tech
16.
Farina, Jordan T.
Application of Multi-Port Mixing for Passive Suppression of Thermo-Acoustic Instabilities in Premixed Combustors.
Degree: PhD, Mechanical Engineering, 2013, Virginia Tech
URL: http://hdl.handle.net/10919/50533
► The utilization of lean premixed combustors has become attractive to designers of industrial gas turbines as a means of meeting strict emissions standards without compromising…
(more)
▼ The utilization of lean premixed combustors has become attractive to designers of industrial gas turbines as a means of meeting strict emissions standards without compromising efficiency. Mixing the fuel and air prior to
combustion allows for lower temperature flame zones, creating the potential for drastically reduced nitrous oxide emissions. While effective, these systems are commonly plagued by
combustion driven
instabilities. These
instabilities produce large pressure and heat release rate fluctuations due to a resonant interaction between the combustor acoustics and the flame. A primary feedback mechanism responsible for driving these systems is the propagation of Fuel/Air Ratio (FAR) fluctuations into the flame zone. These fluctuations are formed inside of the premixing chamber when fuel is injected into and mixed with an oscillating air flow. The research presented here aimed to develop new technology for premixer designs, along with an application strategy, to avoid resonant thermo-acoustic events driven by FAR fluctuations. A passive fuel control technique was selected for investigation and implementation. The selected technique utilized fuel injections at multiple, strategically placed axial locations to target and inhibit FAR fluctuations at the dominant resonant mode of the combustor. The goal of this research was to provide an understanding of the mixing response inside a realistic premixer geometry and investigate the effectiveness of the proposed suppression technique. The mixing response was investigated under non-reacting flow conditions using a unique modular premixer. The premixer incorporated variable axial fuel injection locations, as well as interchangeable mixing chamber geometries. Two different chamber designs were tested: a simple annular chamber and one incorporating an axial swirler. The mixing response of the simple annular geometry was well characterized, and it was found that multiple injections could be effectively configured to suppress the onset of an unstable event at very lean conditions. Energy dense flame zones produced at higher equivalence ratios, however, were found to be uncontrollable using this technique. Additionally, the mixing response of the swirl geometry was difficult to predict. This was found to be the result of large spatial gradients formed in the dynamic velocity field as acoustic waves passed through the swirl vanes.
Advisors/Committee Members: Vandsburger, Uri (committeechair), O'Brien, Walter F. Jr. (committee member), Lattimer, Brian Y. (committee member), West, Robert L. (committee member), Ranalli, Joseph Allen (committee member).
Subjects/Keywords: lean premixed; gas turbines; combustion; thermo-acoustic instabilities; passive control
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APA (6th Edition):
Farina, J. T. (2013). Application of Multi-Port Mixing for Passive Suppression of Thermo-Acoustic Instabilities in Premixed Combustors. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/50533
Chicago Manual of Style (16th Edition):
Farina, Jordan T. “Application of Multi-Port Mixing for Passive Suppression of Thermo-Acoustic Instabilities in Premixed Combustors.” 2013. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/50533.
MLA Handbook (7th Edition):
Farina, Jordan T. “Application of Multi-Port Mixing for Passive Suppression of Thermo-Acoustic Instabilities in Premixed Combustors.” 2013. Web. 28 Feb 2021.
Vancouver:
Farina JT. Application of Multi-Port Mixing for Passive Suppression of Thermo-Acoustic Instabilities in Premixed Combustors. [Internet] [Doctoral dissertation]. Virginia Tech; 2013. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/50533.
Council of Science Editors:
Farina JT. Application of Multi-Port Mixing for Passive Suppression of Thermo-Acoustic Instabilities in Premixed Combustors. [Doctoral Dissertation]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/50533
Virginia Tech
17.
Nord, Lars.
A Thermoacoustic Characterization of a Rijke-type Tube Combustor.
Degree: MS, Mechanical Engineering, 2001, Virginia Tech
URL: http://hdl.handle.net/10919/31437
► Pressure pulsations, or thermoacoustic instabilities, as they are called in the research community, can cause extensive damage in gas turbine combustion chambers. To understand the…
(more)
▼ Pressure pulsations, or thermoacoustic
instabilities, as they are called in the research community, can cause extensive damage in gas turbine
combustion chambers. To understand the phenomena related to thermoacoustics, a simple Rijke-type tube combustor was built and studied. Extensive experimental results, as well as theoretical analyses related to the Rijke tube are presented in this thesis. The results, attributable to both the analyses and the experiments, help explain all the phenomena affecting the acoustic pressure in the combustor. The conclusion is that there are three separate yet related physical processes affecting the acoustic pressure in the tube. The three mechanisms are as follows: a main thermoacoustic instability in accordance to the Rayleigh Criterion; a vibrating flame instability where the flame sheet exhibits mode shapes; and a pulsating flame instability driven by heat losses to the flame stabilizer. All these
instabilities affect the heat released to the gas in the combustor. The energy from the oscillating heat couples with the acoustics of the volume bounded by the tube structure. The experimental results in the study are important in order to obtain model parameters for prediction as well as for achieving control of the
instabilities.
Advisors/Committee Members: Saunders, William R. (committeechair), Burdisso, Ricardo A. (committee member), Vandsburger, Uri (committeecochair).
Subjects/Keywords: flame instabilities; combustion; chemiluminescence; acoustics
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APA (6th Edition):
Nord, L. (2001). A Thermoacoustic Characterization of a Rijke-type Tube Combustor. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/31437
Chicago Manual of Style (16th Edition):
Nord, Lars. “A Thermoacoustic Characterization of a Rijke-type Tube Combustor.” 2001. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/31437.
MLA Handbook (7th Edition):
Nord, Lars. “A Thermoacoustic Characterization of a Rijke-type Tube Combustor.” 2001. Web. 28 Feb 2021.
Vancouver:
Nord L. A Thermoacoustic Characterization of a Rijke-type Tube Combustor. [Internet] [Masters thesis]. Virginia Tech; 2001. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/31437.
Council of Science Editors:
Nord L. A Thermoacoustic Characterization of a Rijke-type Tube Combustor. [Masters Thesis]. Virginia Tech; 2001. Available from: http://hdl.handle.net/10919/31437
18.
Mirat, Clément.
Analyse des instabilités de combustion dans des foyers de centrale thermique fonctionnant au fioul lourd : Analysis of combustion instabilities in thermal power plants operating with heavy fuel oil.
Degree: Docteur es, Energétique, 2015, Châtenay-Malabry, Ecole centrale de Paris
URL: http://www.theses.fr/2015ECAP0037
► Des crises vibratoires ont été constatées dans plusieurs centrales thermiques d’EDF opérant avec du fioul lourd, certaines ayant entraîné l’arrêt du foyer. Ce travail traite…
(more)
▼ Des crises vibratoires ont été constatées dans plusieurs centrales thermiques d’EDF opérant avec du fioul lourd, certaines ayant entraîné l’arrêt du foyer. Ce travail traite des instabilités de
combustion pouvant se déclencher dans ce type de système où le combustible liquide est injecté avec de la vapeur d’eau et où l’écoulement d’air est mis en rotation. Ces phénomènes vibratoires résultent d’un couplage résonant entre la dynamique de la
combustion et l’acoustique du foyer. La réponse acoustique des flammes diphasiques non-prémélangées swirlées reste largement méconnue et est difficilement analysable sur le foyer réel. L’objectif de ce travail est donc d’étudier la stabilité des chaudières EDF à partir de l’analyse de la réponse d’une flamme diphasique non-prémélangée swirlée issue d’un injecteur générique et soumise à des perturbations de la vitesse acoustique. Cette réponse est déterminée sur un dispositif original (DIFAV) équipé d’un swirler et d’un injecteur bi-fluides fonctionnant à la vapeur d’eau et au dodécane. Ce système est constitué des principaux éléments des brûleurs utilisés sur les centrales thermiques EDF à une échelle 1/7000. Le dispositif est conçu pour facilement modifier la géométrie de la tête d’injection, les conditions d’injection de combustible et de vapeur et ainsi contrôler le spray généré. Des visualisations à la sortie d’une buse d’injection montrent l’influence de la topologie de l’écoulement diphasique dans l’injecteur sur la taille des gouttes mesurées dans le spray. Des mesures de taille et de vitesse des gouttes lorsque le rapport des débits de vapeur et de combustible (GLR) est modifié sont réalisées. Ces données comparées à des modèles ont permis d’estimer l’évolution de la taille des gouttes générées par l’injecteur qui équipe les centrales thermiques lorsque le GLR varie. Une analyse modale du foyer DIFAV et d’un modèle simplifié de la chaudière réelle est ensuite menée. Les fréquences propres et les taux d’amortissement du foyer DIFAV sont déterminés expérimentalement en soumettant le système à une modulation acoustique externe. Un modèle acoustique simplifié composé de trois cavités couplées représentatif du brûleur DIFAV est également développé. Des simulations acoustiques réalisées avec COMSOL Multiphysics sur une coupe transverse d’une chaudière générique représentative de la chaudière industrielle permettent d’identifier trois modes à basses fréquences établis entre les plenums et la chambre de
combustion qui sont susceptibles d’être instables. La sensibilité de ces modes à la géométrie du foyer et aux conditions limites est étudiée. La réponse de la flamme générique lorsqu’elle est soumise à des modulations acoustiques de l’écoulement d’air en amont du brûleur est ensuite mesurée sur le banc DIFAV pour différents niveaux d’excitation et deux topologies de flamme lorsque les conditions d’injection sont modifiées. Les mécanismes qui pilotent l’évolution du gain de l’une des fonctions de transfert généralisées (FDF) de la flamme sont étudiés à l’aide de visualisations en…
Advisors/Committee Members: Schuller, Thierry (thesis director).
Subjects/Keywords: Ecoulement swirlé; Spray; Dynamique de la combustion; Instabilités de combustion; Swirl flame; Spray; Combustion dynamics; Thermo-acoustics instabilities
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APA (6th Edition):
Mirat, C. (2015). Analyse des instabilités de combustion dans des foyers de centrale thermique fonctionnant au fioul lourd : Analysis of combustion instabilities in thermal power plants operating with heavy fuel oil. (Doctoral Dissertation). Châtenay-Malabry, Ecole centrale de Paris. Retrieved from http://www.theses.fr/2015ECAP0037
Chicago Manual of Style (16th Edition):
Mirat, Clément. “Analyse des instabilités de combustion dans des foyers de centrale thermique fonctionnant au fioul lourd : Analysis of combustion instabilities in thermal power plants operating with heavy fuel oil.” 2015. Doctoral Dissertation, Châtenay-Malabry, Ecole centrale de Paris. Accessed February 28, 2021.
http://www.theses.fr/2015ECAP0037.
MLA Handbook (7th Edition):
Mirat, Clément. “Analyse des instabilités de combustion dans des foyers de centrale thermique fonctionnant au fioul lourd : Analysis of combustion instabilities in thermal power plants operating with heavy fuel oil.” 2015. Web. 28 Feb 2021.
Vancouver:
Mirat C. Analyse des instabilités de combustion dans des foyers de centrale thermique fonctionnant au fioul lourd : Analysis of combustion instabilities in thermal power plants operating with heavy fuel oil. [Internet] [Doctoral dissertation]. Châtenay-Malabry, Ecole centrale de Paris; 2015. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2015ECAP0037.
Council of Science Editors:
Mirat C. Analyse des instabilités de combustion dans des foyers de centrale thermique fonctionnant au fioul lourd : Analysis of combustion instabilities in thermal power plants operating with heavy fuel oil. [Doctoral Dissertation]. Châtenay-Malabry, Ecole centrale de Paris; 2015. Available from: http://www.theses.fr/2015ECAP0037
University of Alabama
19.
Sequera, Daniel E.
Reduction of combustion noise and instabilities using porous inert material with a swirl-stabilized burner.
Degree: 2011, University of Alabama
URL: http://purl.lib.ua.edu/34954
► Combustion instabilities represent a major problem during operation of power generation systems that can lead to costly shutdown. Combustion instabilities are self excited large amplitude…
(more)
▼ Combustion instabilities represent a major problem during operation of power generation systems that can lead to costly shutdown.
Combustion instabilities are self excited large amplitude pressure oscillations caused by the coupling of unsteady heat release and acoustic modes of the combustor. These oscillations cause fluctuating mechanical loads and fluctuating heat transfer that can result in catastrophic premature failure of components.
Combustion noise, a significant source of noise in gas turbines, can lead to
combustion instabilities.
Combustion noise and
instabilities are different phenomena; however, they both occur due to unsteady heat release of turbulent flames that excites acoustic modes of the combustor. The
instabilities self excite when flame adds energy to the acoustic field at a faster rate than it can dissipate it. Swirl-stabilized
combustion and porous inert medium (PIM)
combustion are two methods that have extensively been used, although independently, for flame stabilization. In this study, the two concepts are combined so that PIM serves as a passive device to mitigate
combustion noise and
instabilities. A PIM insert is placed within the lean premixed, swirl-stabilized combustor to affect the turbulent flow field reducing
combustion noise. This study is the first step for eventual implementation in liquid fuel systems. After presenting the concept, a numerical investigation of the changes in the mean flow field caused by the PIM is presented. Changes in the flow field can be beneficial for noise reduction by optimizing the geometric parameters of the PIM. Next, atmospheric pressure experiments were conducted at low reactant inlet velocity (<10 m/s) and low reactant inlet temperature (<120 °C) to investigate effect of PIM parameters on sound pressure level (SPL), and CO and NOx emissions. Surface and interior
combustion modes were identified and PIM geometric parameters were optimized. Next, a laboratory facility to conduct experiments at high reactant inlet velocity, high inlet air temperature, and high pressure was designed and developed. Results show that the porous insert substantially reduces
combustion noise for a range of operating conditions. Moreover, experiments show that the porous insert can mitigate
combustion instabilities without adversely affecting CO and NOx emissions. (Published By University of Alabama Libraries)
Advisors/Committee Members: Agrawal, Ajay K., Baker, John, Taylor, Robert, Olcmen, Semih, Wiest, John, Agrawal, Ajay, University of Alabama. Dept. of Mechanical Engineering.
Subjects/Keywords: Electronic Thesis or Dissertation; – thesis; Mechanical Engineering; Acoustics; Combustion; Instabilities; Noise; PIM; Porous; Swirl
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APA (6th Edition):
Sequera, D. E. (2011). Reduction of combustion noise and instabilities using porous inert material with a swirl-stabilized burner. (Thesis). University of Alabama. Retrieved from http://purl.lib.ua.edu/34954
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Sequera, Daniel E. “Reduction of combustion noise and instabilities using porous inert material with a swirl-stabilized burner.” 2011. Thesis, University of Alabama. Accessed February 28, 2021.
http://purl.lib.ua.edu/34954.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Sequera, Daniel E. “Reduction of combustion noise and instabilities using porous inert material with a swirl-stabilized burner.” 2011. Web. 28 Feb 2021.
Vancouver:
Sequera DE. Reduction of combustion noise and instabilities using porous inert material with a swirl-stabilized burner. [Internet] [Thesis]. University of Alabama; 2011. [cited 2021 Feb 28].
Available from: http://purl.lib.ua.edu/34954.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Sequera DE. Reduction of combustion noise and instabilities using porous inert material with a swirl-stabilized burner. [Thesis]. University of Alabama; 2011. Available from: http://purl.lib.ua.edu/34954
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Georgia Tech
20.
Lioi, Christopher.
Linear combustion stabiliy analysis of oxidizer-rich staged combustion engines.
Degree: PhD, Aerospace Engineering, 2019, Georgia Tech
URL: http://hdl.handle.net/1853/62579
► This thesis concerns the consistent linear acoustic stability analysis of an engine modeled on the RD-170, a prototypical example of an Oxidizer Rich Staged Combustion…
(more)
▼ This thesis concerns the consistent linear acoustic stability analysis of an engine modeled on the RD-170, a prototypical example of an Oxidizer Rich Staged
Combustion (ORSC) engine. Both the preburner-turbine assembly as well as the main
combustion chamber are studied. The theoretical basis for the stability analysis is an inhomogeneous acoustic wave equation in the pressure. Boundary effects are accounted for by means of impedance boundary conditions. Theoretical impedance models are employed to describe the physics of various components: the turbine inlet blade row in the preburner assembly, and the flow distributor in the main chamber. In the main chamber, mean flow and
combustion response effects are accounted for by means of right hand side source terms in the wave equation. Two cases are considered for mean flow: piecewise uniform and swirl flow. The swirl flow is generated by time averaging the results from LES of the main chamber injectors. It is found that the mean flow contributes significant damping to the system by means of convecting acoustic energy out of the domain. The swirl flow additionally provides acoustic refraction which further increases the damping. Overall the mean flow is found to far eclipse the other sources of damping. The response of the
combustion to acoustic perturbations is quantified by means of a Flame Transfer Function (FTF). Spatially distributed fields for both the FTF gain and phase are computed from LES data using POD reduction for three different injector recess lengths. A chamber-level response field is constructed as a superposition of fields for individual injectors. It is found that as the recess length decreases, the system becomes more unstable, due to the fact that the base of the injector nonpremixed flame becomes more exposed to the transverse oscillations in the main chamber. A sensitivity analysis is conducted on a reduced set of scalar quantities which characterize the distributed
combustion response fields. The eigenvalue results are found to be most sensitive to the maximum of the gain field, the axial spread of the gain about this maximum value, and the maximum axial slope of the phase field. The radial location of the maximum gain also affects the stability to a lesser extent. The results suggest that to maximize the stability margin of the engine the recess length of the injector should be maximized and the fluid conditions should be such that the flame is wide and
combustion is distributed over as large an axial extent as possible.
Advisors/Committee Members: Yang, Vigor (advisor), Ahuja, Krish (committee member), Sankar, Lakshmi (committee member), Lieuwen, Timothy (committee member), Funk, Robert (committee member).
Subjects/Keywords: Combustion instabilities; Acoustics; Liquid rocket engines; ORSC engines; Finite element analysis; LES; Flame transfer function
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APA (6th Edition):
Lioi, C. (2019). Linear combustion stabiliy analysis of oxidizer-rich staged combustion engines. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/62579
Chicago Manual of Style (16th Edition):
Lioi, Christopher. “Linear combustion stabiliy analysis of oxidizer-rich staged combustion engines.” 2019. Doctoral Dissertation, Georgia Tech. Accessed February 28, 2021.
http://hdl.handle.net/1853/62579.
MLA Handbook (7th Edition):
Lioi, Christopher. “Linear combustion stabiliy analysis of oxidizer-rich staged combustion engines.” 2019. Web. 28 Feb 2021.
Vancouver:
Lioi C. Linear combustion stabiliy analysis of oxidizer-rich staged combustion engines. [Internet] [Doctoral dissertation]. Georgia Tech; 2019. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/1853/62579.
Council of Science Editors:
Lioi C. Linear combustion stabiliy analysis of oxidizer-rich staged combustion engines. [Doctoral Dissertation]. Georgia Tech; 2019. Available from: http://hdl.handle.net/1853/62579
Georgia Tech
21.
Bellows, Benjamin Davis.
Characterization of nonlinear heat release-acoustic interactions in gas turbine combustors.
Degree: PhD, Aerospace Engineering, 2006, Georgia Tech
URL: http://hdl.handle.net/1853/10474
► This thesis describes an experimental investigation of the flame transfer function between flow disturbances and heat release oscillations in lean, premixed combustors. This research effort…
(more)
▼ This thesis describes an experimental investigation of the flame transfer function between flow disturbances and heat release oscillations in lean, premixed combustors. This research effort was motivated by the fact that modern gas turbines, operating fuel-lean to minimize exhaust emissions, are susceptible to self-excited
combustion oscillations. These
instabilities generally occur when the unsteady
combustion process couples with the acoustic modes of the
combustion chamber. The resultant flow and structural vibrations can substantially reduce hot section part life. As such, avoiding operating regimes where high dynamics occur often requires operating at lower power outputs and/or higher pollutant emissions than the turbine is otherwise capable.
This work demonstrated nonlinearities in the chemiluminescence response at large amplitude velocity oscillations in a turbulent, swirling flame. It is observed that the nonlinear flame response can exhibit a variety of behaviors, both in the shape of the response curve and the forcing amplitude at which nonlinearity is first observed depending on the operating conditions of the combustor. The phase between the flow oscillations and heat release is also seen to have substantial amplitude dependence. In addition, the interactions between the fundamental frequency and the higher and subharmonics of the measured signals can significantly influence the flame as well as the frequency response of the system.
The nonlinear flame dynamics are governed by different mechanisms in different frequency and flowrate regimes. Three mechanisms, vortex rollup, unsteady flame liftoff, and parametric instability, are identified to influence the nonlinear flame response in these combustors. Analysis of the results shows that the mechanisms responsible for nonlinearity in the flame response are influenced by the Strouhal number, the mean velocity at the combustor dump plane, and the ratio of the oscillating velocity amplitude to the laminar flame speed.
Advisors/Committee Members: Dr. Tim Lieuwen (Committee Chair), Dr. Ben Zinn (Committee Member), Dr. Jeff Jagoda (Committee Member), Dr. Jeffrey Cohen (Committee Member), Dr. Jerry Seitzman (Committee Member).
Subjects/Keywords: Nonlinear flame transfer function; Combustion instabilities
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APA (6th Edition):
Bellows, B. D. (2006). Characterization of nonlinear heat release-acoustic interactions in gas turbine combustors. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/10474
Chicago Manual of Style (16th Edition):
Bellows, Benjamin Davis. “Characterization of nonlinear heat release-acoustic interactions in gas turbine combustors.” 2006. Doctoral Dissertation, Georgia Tech. Accessed February 28, 2021.
http://hdl.handle.net/1853/10474.
MLA Handbook (7th Edition):
Bellows, Benjamin Davis. “Characterization of nonlinear heat release-acoustic interactions in gas turbine combustors.” 2006. Web. 28 Feb 2021.
Vancouver:
Bellows BD. Characterization of nonlinear heat release-acoustic interactions in gas turbine combustors. [Internet] [Doctoral dissertation]. Georgia Tech; 2006. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/1853/10474.
Council of Science Editors:
Bellows BD. Characterization of nonlinear heat release-acoustic interactions in gas turbine combustors. [Doctoral Dissertation]. Georgia Tech; 2006. Available from: http://hdl.handle.net/1853/10474
University of Sydney
22.
Singh, Gajendra.
Atomization and Combustion Characterization of Sprays
.
Degree: University of Sydney
URL: http://hdl.handle.net/2123/23135
► This thesis presents an extensive study of turbulent air-blasted sprays aimed at advancing the current understanding of the atomization and the turbulent combustion of dense…
(more)
▼ This thesis presents an extensive study of turbulent air-blasted sprays aimed at advancing the current understanding of the atomization and the turbulent combustion of dense sprays. The burner employed controls the spray quality by recessing the liquid-injecting needle inside the air-blast tube to transition the spray from dilute to dense. A pilot is used to stabilize the flame to the burner which is sitting in a co-flowing stream of secondary air. Three fuels, acetone, ethanol, and biodiesel, are used to generate several sprays that cover a broad range of non-dimensional numbers.
Probability distributions of wavelength and amplitude of instabilities forming on coaxial air-blast atomizers are measured directly using high-speed shadowgraphs (or back-lit microscopic imaging), in a range of cases that investigate the independent effects of a suite of parameters. The influence of jet velocity and gas velocity on the initiation and growth of jet instabilities is discussed. The range of mechanisms governing the formation of liquid fragments and their relation to surface instabilities is discussed. Previous work suggested that the mean wavelength scales with the boundary layer thickness. This is confirmed here and extended to demonstrate that the wavelength probability distribution correlates well with the ligament length probability distribution. This establishes a direct link between interfacial instabilities and ligament formation in air-assisted primary atomization.
The complete structure of atomizing liquid fragments is analyzed by employing multi-dimensional visualization techniques and advanced image processing, where objects from multiple views are matched to extract three-dimensional information. An in-house MATLAB script is developed to extract the spray volume, which employs the principle of image discretization, where each image is divided into a number of slices, and the individual slice from each camera is matched to compute the liquid volume fraction in each image. The volume of individual objects is calculated based on their planar area and orientation. An error analysis is performed using dozens of three-dimensional virtual models of fragment-like shapes with a known volume. Local characteristics of atomizing fragments are discussed by using the information obtained through the slicing method. A detailed account of fragment statistics are provided for the atomizing sprays.
The LIF-OH-CH2O technique is used to measure the product of OH and CH2O ([OH]*[CH2O]) and hence the heat release zones in turbulent, moderately dense spray flames of ethanol and biodiesel fuels. A combination of several filters is used to remove interference from droplet luminosity. Mie scattering is measured jointly on a separate camera to locate the droplets with respect to the reaction zones. It is found that while the overall flame structure is similar to that of a diffusion flame. Structures referred to as burning rings of different sizes are observed, and these are ignited by heat source before they grow, propagate, and burnout.…
Subjects/Keywords: Spray;
Combustion;
Atomization;
Instabilities;
Optical Diagnostics
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Export
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APA (6th Edition):
Singh, G. (n.d.). Atomization and Combustion Characterization of Sprays
. (Thesis). University of Sydney. Retrieved from http://hdl.handle.net/2123/23135
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Singh, Gajendra. “Atomization and Combustion Characterization of Sprays
.” Thesis, University of Sydney. Accessed February 28, 2021.
http://hdl.handle.net/2123/23135.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Singh, Gajendra. “Atomization and Combustion Characterization of Sprays
.” Web. 28 Feb 2021.
Note: this citation may be lacking information needed for this citation format:
No year of publication.
Vancouver:
Singh G. Atomization and Combustion Characterization of Sprays
. [Internet] [Thesis]. University of Sydney; [cited 2021 Feb 28].
Available from: http://hdl.handle.net/2123/23135.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.
Council of Science Editors:
Singh G. Atomization and Combustion Characterization of Sprays
. [Thesis]. University of Sydney; Available from: http://hdl.handle.net/2123/23135
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
No year of publication.
INP Toulouse
23.
Roux, Anthony.
Simulation aux Grandes Echelles d'un statoréacteur : Large-Eddy Simulation of Ramjets.
Degree: Docteur es, Dynamique des fluides, 2009, INP Toulouse
URL: http://www.theses.fr/2009INPT025H
► La conception d'un statoréacteur bénificie aujourd'hui des progrès divers des outils numériques permettant par la même occasion d'alléger les différentes étapes préliminaires de tests en…
(more)
▼ La conception d'un statoréacteur bénificie aujourd'hui des progrès divers des outils numériques permettant par la même occasion d'alléger les différentes étapes préliminaires de tests en géométrie réelle nécessaires au développement de telle configuration. L'objectif de cette thèse est de développer une méthodologie s'appuyant sur la Simulation aux Grandes Echelles (SGE) afin de contribuer à la validation de ce nouvel outil numérique pour la simulation de statoréacteur et ainsi de contribuer à la compréhension des phénomènes mis en jeu dans ces chambres de combustion. L'outil numérique est tout d'abord adapté pour la simulation des écoulements réactifs fortement turbulents avec un accent mis sur la gestion des chocs avec des schémas centrés et la discrétisation de la convection pour la simulation Eulérienne de la phase dispersée. La configuration cible est le "Statoréacteur de Recherche'' étudié expérimentalement par l'ONERA. Sa simulation est réalisée de manière graduelle. Tout d'abord, il est montré que la simulation de la totalité de la configuration, y compris les diffuseurs d'entrée où se positionne un réseau de choc, est essentielle afin de considérer une géométrie acoustiquement close pour reproduire correctement les modes d'oscillation du statoréacteur. La pertinence du schéma cinétique est aussi étudiée et il est montré l'importance de bien reproduire l'évolution de la vitesse de flamme adiabatique pour une plage de richesse grande, en raison du régime de combustion partiellement prémélangé. Finalement, trois cas à richesse différente sont simulés et un excellent accord est trouvé avec l'expérience. La phénoménologie et les mécanismes pilotant la combustion sont alors étudiés pour ces trois cas.
Design of ramjets benefits today from the progress of numerical tools which relieve the various test stages of real engines that remain necessary for the development of such a kind of configuration. The objective of this dissertation is to develop a methodology based on the Large Eddy Simulation (LES) to contribute to the validation of this new type of advanced numerical tool for the simulation of ramjets and improve the understanding of combustion in these devices. The numerical tool is first adapted for the simulation of highly turbulent reacting flows with emphases on the management of shocks with centered schemes and the discretization of convection for the Eulerian simulation of the dispersed phase. The target configuration is the “Research ramjet” experimentally studied by ONERA. Simulation is carried out gradually. First, it is shown that the simulation of the entire configuration, including diffusers at the inlets where shocks appear is essential to consider an acoustically close geometry to properly reproduce the oscillation modes of combustion. The relevance of the kinetic scheme is also studied. It is shown that reproducing the evolution of the adiabatic flame speed for a wide range of equivalence ratio is critical because of the partially premixed combustion regime involved in this configuration.…
Advisors/Committee Members: Gicquel, Laurent (thesis director), Poinsot, Thierry (thesis director).
Subjects/Keywords: Simulations aux Grandes Echelles; Statoréacteur; Turbulence; Instabilitiés de combustion; Ecoulement Diphasique; Large-Eddy Simulation; Ramjet; Turbulence; Combustion instabilities; Two-Phase Flows
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APA ·
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to Zotero / EndNote / Reference
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APA (6th Edition):
Roux, A. (2009). Simulation aux Grandes Echelles d'un statoréacteur : Large-Eddy Simulation of Ramjets. (Doctoral Dissertation). INP Toulouse. Retrieved from http://www.theses.fr/2009INPT025H
Chicago Manual of Style (16th Edition):
Roux, Anthony. “Simulation aux Grandes Echelles d'un statoréacteur : Large-Eddy Simulation of Ramjets.” 2009. Doctoral Dissertation, INP Toulouse. Accessed February 28, 2021.
http://www.theses.fr/2009INPT025H.
MLA Handbook (7th Edition):
Roux, Anthony. “Simulation aux Grandes Echelles d'un statoréacteur : Large-Eddy Simulation of Ramjets.” 2009. Web. 28 Feb 2021.
Vancouver:
Roux A. Simulation aux Grandes Echelles d'un statoréacteur : Large-Eddy Simulation of Ramjets. [Internet] [Doctoral dissertation]. INP Toulouse; 2009. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2009INPT025H.
Council of Science Editors:
Roux A. Simulation aux Grandes Echelles d'un statoréacteur : Large-Eddy Simulation of Ramjets. [Doctoral Dissertation]. INP Toulouse; 2009. Available from: http://www.theses.fr/2009INPT025H
24.
Rutard, Nicolas.
Simulation numérique et modélisation de l'influence d'ondes acoustiques de haute amplitude sur un jet diphasique : application au domaine de la propulsion fusée à ergols liquides : Numerical simulation and modelling of the influence of high-amplitude acoustic waves on a two-phase jet : application to the field of liquid-propellant rocket propulsion.
Degree: Docteur es, Énergétique, 2019, Université Paris-Saclay (ComUE)
URL: http://www.theses.fr/2019SACLC088
► L’occurrence d'instabilités de combustion de haute fréquence au sein des moteurs-fusées à ergols liquides peut s'avérer dommageable pour l'intégrité des systèmes propulsifs. Par conséquent, les…
(more)
▼ L’occurrence d'instabilités de combustion de haute fréquence au sein des moteurs-fusées à ergols liquides peut s'avérer dommageable pour l'intégrité des systèmes propulsifs. Par conséquent, les acteurs du spatial souhaitent renforcer leur compréhension des mécanismes à l'origine de ces instabilités. Pour cela, la simulation numérique s'est révélée au fil du temps de plus en plus attractive. Dans le cas particulier d'un fonctionnement en régime subcritique, le comburant se trouve à l'état liquide dans la chambre de combustion. Pour reproduire fidèlement les écoulements associés à ce régime de fonctionnement, la simulation numérique doit pouvoir restituer les mécanismes d'interaction entre les perturbations acoustiques et le processus d'atomisation de la phase liquide, car ils peuvent influencer la stabilité de la combustion. Dans cette optique, cette étude consiste 1) à mettre en place une méthodologie de simulation numérique de jet diphasique atomisé sous excitation acoustique, 2) à valider la restitution de l'ensemble des mécanismes de réponse du jet aux ondes acoustiques, et 3) à s'appuyer sur les résultats des simulations pour progresser vers une meilleure compréhension des phénomènes physiques mis en jeu. La stratégie de simulation utilisée est basée sur le couplage entre une méthode à interface diffuse à 4 équations pour simuler le gaz et les plus grosses structures liquides de l'écoulement, et une approche statistique Eulérienne pour modéliser le spray de gouttes. Dans ces travaux, la simulation numérique d'un jet diphasique atomisé soumis à une excitation acoustique de haute amplitude montre une bonne restitution de l'aplatissement du cœur liquide et de son influence sur le processus d'atomisation du jet. Notamment, le cœur liquide est raccourci et le spray s'élargit dans la direction orthogonale à l'axe de propagation acoustique. Un couplage important d'ores et déjà observé expérimentalement entre le système d'injection et la cavité acoustique ainsi que son influence sur le processus d'atomisation de la phase liquide sont également reproduits. Enfin, une modélisation simplifiée de l'écoulement destinée à compléter les résultats des simulations révèle une déviation progressive du cœur liquide, et donc des gouttes issues de son atomisation, par la force de radiation acoustique. Ces travaux ouvrent ainsi la voie à des simulations réactives capables de reproduire fidèlement le comportement de flammes diphasiques sous perturbation acoustique en vue d'en étudier l'impact sur la stabilité de la combustion.
The occurrence of high-frequency combustion instabilities in liquid-propellant rocket engines can be detrimental to propulsion systems. Consequently, space actors need to strengthen their understanding of the mechanisms that cause these instabilities. To this end, numerical simulation has become more and more attractive over time. Under subcritical operating conditions, the oxidizer inside the combustion chamber is in a liquid state. In such a case, numerical simulation must be able to reproduce every…
Advisors/Committee Members: Ducruix, Sébastien (thesis director).
Subjects/Keywords: Instabilités de combustion; Régime subcritique; LES; Injection coaxiale; Pression de radiation; Combustion instabilities; Subcritical conditions; LES; Coaxial injection; Radiation pressure
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APA (6th Edition):
Rutard, N. (2019). Simulation numérique et modélisation de l'influence d'ondes acoustiques de haute amplitude sur un jet diphasique : application au domaine de la propulsion fusée à ergols liquides : Numerical simulation and modelling of the influence of high-amplitude acoustic waves on a two-phase jet : application to the field of liquid-propellant rocket propulsion. (Doctoral Dissertation). Université Paris-Saclay (ComUE). Retrieved from http://www.theses.fr/2019SACLC088
Chicago Manual of Style (16th Edition):
Rutard, Nicolas. “Simulation numérique et modélisation de l'influence d'ondes acoustiques de haute amplitude sur un jet diphasique : application au domaine de la propulsion fusée à ergols liquides : Numerical simulation and modelling of the influence of high-amplitude acoustic waves on a two-phase jet : application to the field of liquid-propellant rocket propulsion.” 2019. Doctoral Dissertation, Université Paris-Saclay (ComUE). Accessed February 28, 2021.
http://www.theses.fr/2019SACLC088.
MLA Handbook (7th Edition):
Rutard, Nicolas. “Simulation numérique et modélisation de l'influence d'ondes acoustiques de haute amplitude sur un jet diphasique : application au domaine de la propulsion fusée à ergols liquides : Numerical simulation and modelling of the influence of high-amplitude acoustic waves on a two-phase jet : application to the field of liquid-propellant rocket propulsion.” 2019. Web. 28 Feb 2021.
Vancouver:
Rutard N. Simulation numérique et modélisation de l'influence d'ondes acoustiques de haute amplitude sur un jet diphasique : application au domaine de la propulsion fusée à ergols liquides : Numerical simulation and modelling of the influence of high-amplitude acoustic waves on a two-phase jet : application to the field of liquid-propellant rocket propulsion. [Internet] [Doctoral dissertation]. Université Paris-Saclay (ComUE); 2019. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2019SACLC088.
Council of Science Editors:
Rutard N. Simulation numérique et modélisation de l'influence d'ondes acoustiques de haute amplitude sur un jet diphasique : application au domaine de la propulsion fusée à ergols liquides : Numerical simulation and modelling of the influence of high-amplitude acoustic waves on a two-phase jet : application to the field of liquid-propellant rocket propulsion. [Doctoral Dissertation]. Université Paris-Saclay (ComUE); 2019. Available from: http://www.theses.fr/2019SACLC088
INP Toulouse
25.
Kaiser, Thomas.
Impact of flow rotation on flame dynamics and hydrodynamic stability : Influence de la rotation de l'écoulement sur la dynamique des flammes et la stabilité hydrodynamique.
Degree: Docteur es, Dynamique des fluides, 2019, INP Toulouse
URL: http://www.theses.fr/2019INPT0011
► Cette thèse a pour but l’étude de la rotation de l’écoulement des grandes échelles dans deux configurations. La première configuration se concentre sur l’effet de…
(more)
▼ Cette thèse a pour but l’étude de la rotation de l’écoulement des grandes échelles dans deux configurations. La première configuration se concentre sur l’effet de la rotation de l’écoulement sur une flamme laminaire. Elle est stabilisée dans le sillage d’un cylindre. La rotation de l’écoulement est introduite en faisant tourner le cylindre autour de son axe. La simulation numérique directe (Direct Numerical Simulation (DNS)) montre que la rotation du cylindre rompt la symétrie des deux branches de la flamme. La fonction de transfert de flamme (Flame Transfer Function (FTF)), obtenue grâce à l’inversion de Wiener-Hopf, indique qu’un faible taux de rotation réduit le gain de la FTF et donc la flamme devient presque insensible aux perturbations acoustiques à une fréquence donnée. De plus, il est démontré que cette diminution du gain est due à une interférence destructive des fluctuations de chaleur produites par les deux branches de la flamme. La fréquence à laquelle le gain de la FTF devient presque nul est ajustable par la vitesse de rotation du cylindre. Cette étude suggère que le contrôle de la symétrie de la flamme pourrait être un outil de contrôle en boucle ouverte des instabilités thermoacoustiques. Dans le cas de la deuxième configuration, la rotation de l’écoulement est induite par une instabilité hydrodynamique, aussi nommée Precessing Vortex Core (PVC) dans un système d’injection de carburant industriel. Des expériences et des simulations aux grandes échelles (Large Eddy Simulation (LES)) montrent que l’écoulement non-réactif dans l’injecteur pri- maire peut être décomposé en une contribution moyenne et un PVC. Cette instabilité hydro- dynamique est étudiée par l’analyse de stabilité linéaire (Linear Stability Analysis (LSA)) en utilisant deux approches différentes (locale et BiGlobale). Les résultats de l’expérience, de la LES et de la LSA démontrent que le montage d’une tige centrale à l’intérieur de l’injecteur stabilise le PVC. De plus, le même injecteur industriel est étudié dans le cas d’un écoule- ment réactif par LES. Les résultats démontrent que la flamme stabilise le PVC. L’analyse de stabilité BiGlobal montre que le gradient de densité dans le front moyen de la flamme a un effet important sur l’amortissement du PVC. Enfin, l’impact de la tige centrale est également étudié pour le cas réactif. La tige centrale impacte marginalement la forme globale de la flamme, mais a un effet positif sur l’accrochage de la flamme dans la zone de combustion pauvre. En comparant deux cas par LSA, celui avec la tige et celui sans la tige, les résultats suggèrent que la tige augmente considérablement l’amortissement du PVC. Cela pourrait causer une diminution de la turbulence dans l’écoulement et empêcher l’extinction de la flamme et donc expliquer l’influence bénéfique de la tige sur la stabilisation de la flamme.
This thesis investigates large scale flow rotation in two configurations. In the first, the effect of flow rotation on a laminar flame is investigated. The flame is anchored in the wake of a cylindrical…
Advisors/Committee Members: Poinsot, Thierry (thesis director), Selle, Laurent (thesis director).
Subjects/Keywords: Instabilités de combustion; Analyses de stabilité; Acoustique; Dynamique des flammes; Combustion instabilities; Stability analysis; Acoustics; Flame dynamics; 530
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APA (6th Edition):
Kaiser, T. (2019). Impact of flow rotation on flame dynamics and hydrodynamic stability : Influence de la rotation de l'écoulement sur la dynamique des flammes et la stabilité hydrodynamique. (Doctoral Dissertation). INP Toulouse. Retrieved from http://www.theses.fr/2019INPT0011
Chicago Manual of Style (16th Edition):
Kaiser, Thomas. “Impact of flow rotation on flame dynamics and hydrodynamic stability : Influence de la rotation de l'écoulement sur la dynamique des flammes et la stabilité hydrodynamique.” 2019. Doctoral Dissertation, INP Toulouse. Accessed February 28, 2021.
http://www.theses.fr/2019INPT0011.
MLA Handbook (7th Edition):
Kaiser, Thomas. “Impact of flow rotation on flame dynamics and hydrodynamic stability : Influence de la rotation de l'écoulement sur la dynamique des flammes et la stabilité hydrodynamique.” 2019. Web. 28 Feb 2021.
Vancouver:
Kaiser T. Impact of flow rotation on flame dynamics and hydrodynamic stability : Influence de la rotation de l'écoulement sur la dynamique des flammes et la stabilité hydrodynamique. [Internet] [Doctoral dissertation]. INP Toulouse; 2019. [cited 2021 Feb 28].
Available from: http://www.theses.fr/2019INPT0011.
Council of Science Editors:
Kaiser T. Impact of flow rotation on flame dynamics and hydrodynamic stability : Influence de la rotation de l'écoulement sur la dynamique des flammes et la stabilité hydrodynamique. [Doctoral Dissertation]. INP Toulouse; 2019. Available from: http://www.theses.fr/2019INPT0011
Delft University of Technology
26.
Sliphorst, M.
High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers.
Degree: 2011, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283
;
urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283
;
urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283
;
http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283
► Ever since the early stages of space transportation in the 1940’s, and the related liquid propellant rocket engine development, combustion instability has been a major…
(more)
▼ Ever since the early stages of space transportation in the 1940’s, and the related liquid propellant rocket engine development,
combustion instability has been a major issue. High frequency
combustion instability (HFCI) is the interaction between
combustion and the acoustic field in the
combustion chamber. It destroys the thermal boundary layer wall increasing heat transfer and could lead to compromised performance, and ultimately to destruction of the engine and mission loss. The main objective of this thesis is to take a few steps toward a better physical understanding of HFCI by experimentally investigating the interaction between flame and acoustic field in a combustor specifically designed for this research. With the large amount of collected data, well-defined spatially and temporally resolved acoustic fields of the first eigenmode were found with a high degree of consistency. These acoustic fields were successfully correlated with measured flame emission, and substantiated the conclusions with respect to coupling and driving mechanisms of HFCI.
Advisors/Committee Members: Roekaerts, D.J.E.M..
Subjects/Keywords: combustion; combustion instabilities; HF-instabilities; acoustics; eigenmodes; spray combustion; resonant combustion; resonance; Rayleigh criterion; response factor
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APA (6th Edition):
Sliphorst, M. (2011). High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers. (Doctoral Dissertation). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283 ; urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283 ; urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283 ; http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283
Chicago Manual of Style (16th Edition):
Sliphorst, M. “High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers.” 2011. Doctoral Dissertation, Delft University of Technology. Accessed February 28, 2021.
http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283 ; urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283 ; urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283 ; http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283.
MLA Handbook (7th Edition):
Sliphorst, M. “High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers.” 2011. Web. 28 Feb 2021.
Vancouver:
Sliphorst M. High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers. [Internet] [Doctoral dissertation]. Delft University of Technology; 2011. [cited 2021 Feb 28].
Available from: http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283 ; urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283 ; urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283 ; http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283.
Council of Science Editors:
Sliphorst M. High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers. [Doctoral Dissertation]. Delft University of Technology; 2011. Available from: http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283 ; urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283 ; urn:NBN:nl:ui:24-uuid:403ca079-82db-4d09-9676-c3b38c007283 ; http://resolver.tudelft.nl/uuid:403ca079-82db-4d09-9676-c3b38c007283
27.
Perovšek, Jaka.
Ray Tracing and Spectral Modelling of Excited Hydroxyl Radiation from Cryogenic Flames in Rocket Combustion Chambers.
Degree: Electrical and Space Engineering, 2018, Luleå University of Technology
URL: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71277
► A visualisation procedure was developed which predicts excited hydroxyl (OH*) radiation from the Computational Fluid Dynamics (CFD) solutions of cryogenic hydrogen-oxygen rocket flames. The…
(more)
▼ A visualisation procedure was developed which predicts excited hydroxyl (OH*) radiation from the Computational Fluid Dynamics (CFD) solutions of cryogenic hydrogen-oxygen rocket flames. The model of backward ray tracing through inhomogeneous media with a continuously changing refractive index was implemented. It obtains the optical paths of light rays that originate in the rocket chamber, pass through the window and enter a simulated camera. Through the use of spectral modelling, the emission and absorption spectra eλ and κλ are simulated on the ray path from information about temperature, pressure and concentration of constituent species at relevant points. By solving a radiative transfer equation with the integration of emission and absorption spectra along the ray line-by-line, a spectral radiance is calculated, multiplied with the spectral filter transmittance and then integrated into total radiance. The values of total radiances at the window edge are visualised as a simulated 2D image. Such images are comparable with the OH* measurement images. The modelling of refraction effects results in up to 20 % of total radiance range absolute difference compared to line-of-sight integration. The implementation of accurate self-absorption corrects significant over-prediction, which occurs if the flame is assumed to be optically thin. Modelling of refraction results in images with recognisable areas where the effect of a liquid oxygen (LOx) jet core can be observed, as the light is significantly refracted. The algorithm is parallelised and thus ready for use on big computational clusters. It uses partial pre-computation of spectra to reduce computational effort.
Subjects/Keywords: spectral modelling; excited hydroxyl radiation; OH* radiation; ray tracing; spectroscopy; rocket combustion chambers; rocket engines; hydrogen-oxygen combustion; combustion instabilities; Aerospace Engineering; Rymd- och flygteknik
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APA ·
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MLA ·
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CSE |
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APA (6th Edition):
Perovšek, J. (2018). Ray Tracing and Spectral Modelling of Excited Hydroxyl Radiation from Cryogenic Flames in Rocket Combustion Chambers. (Thesis). Luleå University of Technology. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71277
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Perovšek, Jaka. “Ray Tracing and Spectral Modelling of Excited Hydroxyl Radiation from Cryogenic Flames in Rocket Combustion Chambers.” 2018. Thesis, Luleå University of Technology. Accessed February 28, 2021.
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71277.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Perovšek, Jaka. “Ray Tracing and Spectral Modelling of Excited Hydroxyl Radiation from Cryogenic Flames in Rocket Combustion Chambers.” 2018. Web. 28 Feb 2021.
Vancouver:
Perovšek J. Ray Tracing and Spectral Modelling of Excited Hydroxyl Radiation from Cryogenic Flames in Rocket Combustion Chambers. [Internet] [Thesis]. Luleå University of Technology; 2018. [cited 2021 Feb 28].
Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71277.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Perovšek J. Ray Tracing and Spectral Modelling of Excited Hydroxyl Radiation from Cryogenic Flames in Rocket Combustion Chambers. [Thesis]. Luleå University of Technology; 2018. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71277
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
28.
O'Connor, Jacqueline.
Response of a swirl-stabilized flame to transverse acoustic excitation.
Degree: PhD, Aerospace Engineering, 2011, Georgia Tech
URL: http://hdl.handle.net/1853/43756
► This work addresses the issue of transverse combustion instabilities in annular gas turbine combustor geometries. While modern low-emissions combustion strategies have made great strides in…
(more)
▼ This work addresses the issue of transverse
combustion instabilities in annular gas turbine combustor geometries. While modern low-emissions
combustion strategies have made great strides in reducing the production of toxic emissions in aircraft engines and power generation gas turbines,
combustion instability remains one of the foremost technical challenges in the development of next generation combustor technology. To that end, this work investigates the response of a swirling flow and swirl-stabilized flame to a transverse acoustic field is using a variety of high-speed laser techniques, especially high-speed particle image velocimetry (PIV) for detailed velocity measurements of this highly unsteady flow phenomenon. A description of the velocity-coupled transverse instability mechanism is explained with companion measurements describing each of the velocity disturbance pathways. Dependence on acoustic frequency, amplitude, and field symmetry is discussed. Significant emphasis is placed on the response of a swirling flow field to a transverse acoustic field. Details of the dynamics of the vortex breakdown bubble and the shear layers are explained using a wide variety of measurements for both non-reacting and reacting flow cases. This thesis concludes with an overview of the impact of this work and suggestions for future research in this area.
Advisors/Committee Members: Tim Lieuwen (Committee Chair), Ari Glezer (Committee Member), Jerry Seitzman (Committee Member), Lakshmi Sankar (Committee Member), Suresh Menon (Committee Member).
Subjects/Keywords: Swirl-stabilized flame; Combustion instabilities; Transverse instabilities; Vortex breakdown; Acoustic excitation; Combustion; Flame; Gas-turbines Combustion
…issue of transverse combustion instabilities in annular gas
turbine combustor geometries… …instabilities have long plagued the development and operation of
high performance combustion… …instabilities have been studied in a variety of combustion
technologies, but in gas turbine engines in… …practical interest.
The first occurs in annular combustion systems, such as the
instabilities in… …encountered in can combustion systems.
These
instabilities occur at relatively high frequencies…
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APA ·
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APA (6th Edition):
O'Connor, J. (2011). Response of a swirl-stabilized flame to transverse acoustic excitation. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/43756
Chicago Manual of Style (16th Edition):
O'Connor, Jacqueline. “Response of a swirl-stabilized flame to transverse acoustic excitation.” 2011. Doctoral Dissertation, Georgia Tech. Accessed February 28, 2021.
http://hdl.handle.net/1853/43756.
MLA Handbook (7th Edition):
O'Connor, Jacqueline. “Response of a swirl-stabilized flame to transverse acoustic excitation.” 2011. Web. 28 Feb 2021.
Vancouver:
O'Connor J. Response of a swirl-stabilized flame to transverse acoustic excitation. [Internet] [Doctoral dissertation]. Georgia Tech; 2011. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/1853/43756.
Council of Science Editors:
O'Connor J. Response of a swirl-stabilized flame to transverse acoustic excitation. [Doctoral Dissertation]. Georgia Tech; 2011. Available from: http://hdl.handle.net/1853/43756
29.
Allison, Patton Manuel.
Experimental Characterization of Combustion Instabilities and Flow-Flame Dynamics in a Partially-Premixed Gas Turbine Model Combustor.
Degree: PhD, Aerospace Engineering, 2013, University of Michigan
URL: http://hdl.handle.net/2027.42/102385
► Partially-premixed, swirl combustion is applied in gas turbine combustors to achieve flame stabilization and reduced emission production. However, this method is also inherently sensitive to…
(more)
▼ Partially-premixed, swirl
combustion is applied in gas turbine combustors to achieve flame stabilization and reduced emission production. However, this method is also inherently sensitive to
combustion instabilities which can cause large pressure, velocity, and heat release fluctuations. This thesis investigates thermoacoustic coupling created by flow-flame dynamics in a gas turbine model combustor (GTMC) for a variety of fuels and operating flow rates. Several naturally occurring instability modes were identified to control the acoustic response of the system, including Helmholtz resonances from the plenum and convective-acoustic effects which cause equivalence ratio oscillations. Laser Doppler velocimetry was used to measure radial flow in the GTMC, which can set up flow-fields which create loudly resonating flat-shaped flames, in comparison to quiet V-shaped flames. Flame location and shape altered convective time delays which determine the relative phases of pressure and heat release oscillations. Simultaneous pressure and chemiluminescence imaging showed that the heat release, pressure fluctuations, and flame motion are all coupled at the same instability frequency. Videos of the flame motion also revealed that the precessing vortex core (PVC), created by the swirling flow, influences the rocking behavior of the flame. Acetone was added to the fuel to act as a tracer in fluorescence measurements which indicated the localization of unburned fuel. It was discovered that fuel was distributed in lobes which corresponded to locations surrounding the shear layer outside of the central recirculation zone, and that the relative distribution of the lobes adjusted to forcing by the flow. Finally, high-speed formaldehyde planar laser-induced fluorescence was applied to study the motion of preheat zone surfaces in response to the oscillations of the instability. The flame surface density and wrinkling fluctuated at the acoustic frequency and displayed dampened motions correlated with the PVC precession. In non-resonating flames, the behavior of the formaldehyde structure and marked flame surfaces were dominated by the PVC motion, but the degree of surface area fluctuations was reduced compared to unstable flames.
Instabilities in the GTMC are driven by a complex combination of thermoacoustic and flow-field couplings which are influenced by the operational conditions, fueling, mixing, and convective time delays.
Advisors/Committee Members: Driscoll, James F. (committee member), Ihme, Matthias (committee member), Sick, Volker (committee member), Gamba, Mirko (committee member).
Subjects/Keywords: Combustion Instabilities; Laser Diagnostics; Aerospace Engineering; Engineering
…leading to combustion instabilities. . . . . . . . . . . . . . . . . .
Schematic showing the… …However, operation in this regime is highly susceptible to
combustion instabilities. Despite the… …lining due to large
pressure fluctuations.
1
Combustion instabilities present complex cases… …pressure and velocity fields, combustion instabilities can occur which
result in large scale heat… …combustion instabilities. The helical motion of the
6
Figure 1.3: Isosurface of low pressure to…
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APA ·
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APA (6th Edition):
Allison, P. M. (2013). Experimental Characterization of Combustion Instabilities and Flow-Flame Dynamics in a Partially-Premixed Gas Turbine Model Combustor. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/102385
Chicago Manual of Style (16th Edition):
Allison, Patton Manuel. “Experimental Characterization of Combustion Instabilities and Flow-Flame Dynamics in a Partially-Premixed Gas Turbine Model Combustor.” 2013. Doctoral Dissertation, University of Michigan. Accessed February 28, 2021.
http://hdl.handle.net/2027.42/102385.
MLA Handbook (7th Edition):
Allison, Patton Manuel. “Experimental Characterization of Combustion Instabilities and Flow-Flame Dynamics in a Partially-Premixed Gas Turbine Model Combustor.” 2013. Web. 28 Feb 2021.
Vancouver:
Allison PM. Experimental Characterization of Combustion Instabilities and Flow-Flame Dynamics in a Partially-Premixed Gas Turbine Model Combustor. [Internet] [Doctoral dissertation]. University of Michigan; 2013. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/2027.42/102385.
Council of Science Editors:
Allison PM. Experimental Characterization of Combustion Instabilities and Flow-Flame Dynamics in a Partially-Premixed Gas Turbine Model Combustor. [Doctoral Dissertation]. University of Michigan; 2013. Available from: http://hdl.handle.net/2027.42/102385
30.
Gutiérrez, Daniel.
Green Fuel Simulations.
Degree: Engineering Sciences and Mathematics, 2020, Luleå University of Technology
URL: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79244
► Many industries have entered a new global phase which takes the environment in mind. The gas turbine industry is no exception, where the utilization…
(more)
▼ Many industries have entered a new global phase which takes the environment in mind. The gas turbine industry is no exception, where the utilization of green fuels is the future to spare the environment from carbon dioxide and NOx emissions. Hydrogen has been identified as a fuel which can fulfil the global requirements set by governments worldwide. Combustion instabilities are not inevitable during gas turbine operations, especially when using a highly reactive and diffusive fuel as hydrogen. These thermoacoustics instabilities can damage mechanical components and have economic consequences in terms of maintenance and reparation. Understanding these thermoacoustic instabilities in gas turbine burners is of great interest. COMSOL Multiphysics offers a robust acoustic module compared to other available acoustic simulation programs. In this thesis, an Acoustic finite element model was built representing an atmospheric combustion rig (ACR), used to test the burners performance and NOx emissions. Complementary computational fluid dynamics (CFD) simulations were performed for 100 % hydrogen as fuel by using the Reynolds average Navier-Stokes (RANS) lag EB k - epsilon turbulence model. Necessary data was successfully imported to the Acoustic finite element model. Different techniques of building the mesh were used in COMSOL Multiphysics and NX. Similar results were obtained, proving that both mesh tools work well in acoustic simulations. Two different ways of solving the eigenvalue problem in acoustics were implemented, the classic Helmholtz equation and Linearized Navier-Stokes equations, both in the frequency domain. The Helmholtz equation proved to be efficient and detected multiple modes in the frequency range of interest. Critical modes which lived in the burner and the combustion chamber were identified. Defining a hard and soft wall boundary condition at the inlets and outlet of the atmospheric combustion rig gave similar eigenfrequencies when comparing the two boundary conditions. The soft wall boundary condition was defined with a characteristic impedance, giving a high uncertainty whether the results were trustworthy or not. A boundary condition study revealed that the boundary condition at the outlet was valid for modes living in the burner and combustion chamber. Solving the eigenvalue problem with the Linearized Navier-Stokes equations proved to be computationally demanding compared to the Helmholtz equation. Similar modes shapes were found at higher frequencies, but pressure perturbations were observed in the region where the turbulence was dominant. A prestudy for a stability analysis was established, where the ACR and the flame was represented as a generic model. Implementing a Flame Transfer Function (FTF), more specifically a linear n - tau model, showed that the time delay tau is most sensible for a parametric change and hence needs to be chosen cautiously
Subjects/Keywords: Industrial gas turbines; Combustion instabilities; Computational fluid dynamics; Acoustics; COMSOL Multiphysics; Flame transfer function; Fluid Mechanics and Acoustics; Strömningsmekanik och akustik
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APA ·
Chicago ·
MLA ·
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Export
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Manager
APA (6th Edition):
Gutiérrez, D. (2020). Green Fuel Simulations. (Thesis). Luleå University of Technology. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79244
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Gutiérrez, Daniel. “Green Fuel Simulations.” 2020. Thesis, Luleå University of Technology. Accessed February 28, 2021.
http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79244.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Gutiérrez, Daniel. “Green Fuel Simulations.” 2020. Web. 28 Feb 2021.
Vancouver:
Gutiérrez D. Green Fuel Simulations. [Internet] [Thesis]. Luleå University of Technology; 2020. [cited 2021 Feb 28].
Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79244.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Gutiérrez D. Green Fuel Simulations. [Thesis]. Luleå University of Technology; 2020. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79244
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
◁ [1] [2] [3] ▶
. 
Open Access Theses and Dissertations
